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Protocol for the examination of specimens from patients with tumors of soft tissue.

The College of American Pathologists offers these protocols to assist pathologists in providing clinically useful and relevant information when reporting results of surgical specimen examinations of surgical specimens. The College regards the reporting elements in the "Surgical Pathology Cancer Case Summary (Checklist)" portion of the protocols as essential elements of the pathology report. However, the manner in which these elements are reported is at the discretion of each specific pathologist, taking into account clinician preferences, institutional policies, and individual practice.

The College developed these protocols as an educational tool to assist pathologists in the useful reporting of relevant information. It did not issue the protocols for use in litigation, reimbursement, or other contexts. Nevertheless, the College recognizes that the protocols might be used by hospitals, attorneys, payers, and others. Indeed, effective January 1,2004, the Commission on Cancer of the American College of Surgeons mandated the use of the checklist elements of the protocols as part of its Cancer Program Standards for Approved Cancer Programs. Therefore, it becomes even more important for pathologists to familiarize themselves with these documents. At the same time, the College cautions that use of the protocols other than for their intended educational purpose may involve additional considerations that are beyond the scope of these documents.

PROTOCOL FOR THE EXAMINATION OF SPECIMENS FROM PATIENTS WITH TUMORS OF SOFT TISSUE

This protocol applies to soft tissue tumors of intermediate (locally aggressive) and intermediate (rarely metastasizing) potential and malignant soft tissue tumors. The seventh edition TNM staging system of the American Joint Committee on Cancer (AjCC) and the International Union Against Cancer (UICC) for soft tissue is recommended.

Important Note.--These recommendations are designed to be applied principally to soft tissue sarcomas in teenagers and adults because pediatric sarcomas are, in general, treated under strict protocols that may differ significantly from the recommendations supplied herein. (1)

SURGICAL PATHOLOGY CANCER CASE SUMMARY (CHECKLIST)

Soft Tissue: Biopsy

Select a Single Response Unless Otherwise Indicated

* Data elements with asterisks are not required. However, these elements may be clinically important but are not yet validated or regularly used in patient management.

Procedure (note A)

--Core needle biopsy

--Incisional biopsy

--Excisional biopsy

--Other (specify):--

--Not specified

Tumor Site

Specify (if known):--

--Not specified

Tumor Size (note B)

Greatest dimension:--cm

* Additional dimensions:--x--cm

--Cannot be determined (see "Comment")

Macroscopic Extent of Tumor (select all that apply)

--Superficial

--Dermal

--Subcutaneous/suprafascial

--Deep

--Fascial

--Subfascial

--Intramuscular

--Mediastinal

--Intra-abdominal

--Retroperitoneal

--Head and neck

--Other (specify):--

--Cannot be determined

Histologic Type (note C)

Specify:--

--Cannot be determined

Mitotic Rate (note D)

Specify:--/10 high-power fields (HPF)

(1 HPF X 400 = 0.1734 m[m.sup.2]; X 40 objective; most proliferative area)

Necrosis (note D)

--Not identified

--Present

Extent:--%

--Cannot be determined

Histologic Grade (note D)

--Grade 1

--Grade 2

--Grade 3

--Ungraded sarcoma

--Cannot be determined

Margins (for excisional biopsy only) (note E)

--Cannot be assessed

--Margins negative for sarcoma

Distance of sarcoma from closest margin:--cm

Specify margin:--

Specify other close (< 2.0 cm) margin(s):

--Margin(s) positive for sarcoma

Specify margin(s):--

* Lymph-Vascular Invasion (note F)

*--Not identified

*--Present

*--Indeterminate

* Additional Pathologic Findings

* Specify:--

Ancillary Studies

Immunohistochemistry

Specify:--

--Not performed

Cytogenetics

Specify:--

--Not performed

Molecular Pathology

Specify:--

--Not performed

Prebiopsy Treatment (select all that apply)

--No therapy

--Chemotherapy performed

--Radiation therapy performed

--Therapy performed, type not specified

--Unknown

Treatment Effect (note G)

--Not identified

--Present

* Specify percentage of viable tumor:--%

--Cannot be determined

* Comment(s):

SURGICAL PATHOLOGY CANCER CASE SUMMARY (CHECKLIST)

Soft Tissue: Resection

Select a Single Response Unless Otherwise Indicated

* Data elements with asterisks are not required. However, these elements may be clinically important, but are not yet validated or regularly used in patient management.

Procedure (note H)

--Intralesional resection

--Marginal resection

--Wide resection

--Radical resection

--Other (specify):--

--Not specified

Tumor Site

Specify (if known):--

--Not specified

Tumor Size

Greatest dimension:--cm

* Additional dimensions:--X cm

--Cannot be determined (see "Comment")

Macroscopic Extent of Tumor (select all that apply)

--Superficial

--Dermal

--Subcutaneous/suprafascial

--Deep

--Fascial

--Subfascial

--Intramuscular

--Mediastinal

--Intra-abdominal

--Retroperitoneal

--Head and neck

--Other (specify):--

--Cannot be determined

Histologic (notes C and I)

Specify:--

--Cannot be determined

Mitotic Rate (note D)

Specify:--/10 high-power fields (HPF)

(1 HPF X400 = 0.1734 [mm.sup.2]; X40 objective; most proliferative area)

Necrosis (macroscopic or microscopic) (note D)

--Not identified

--Present

Extent:--%

Histologic Grade (note D)

--Grade 1

--Grade 2

--Grade 3

--Ungraded sarcoma

--Cannot be determined

Margins (note E)

--Cannot be assessed

--Margins negative for sarcoma

Distance of sarcoma from closest margin:--cm

Specify margin:--

Specify other close (< 2.0 cm) margin(s):

--Margin(s) positive for sarcoma

Specify margin(s):--

* Lymph-Vascular Invasion (note F)

*--Not identified

*--Present

*--Indeterminate

Pathologic Staging (pTNM) (note J)

TNM Descriptors (required only if applicable) (select all that apply)

--m (multiple)

--r (recurrent)

--y (posttreatment)

Primary Tumor (pT)

--pTX: Primary tumor cannot be assessed

--pT0: No evidence of primary tumor

--pT1a: Tumor 5 cm or less in greatest dimension, superficial tumor

--pT1b: Tumor 5 cm or less in greatest dimension, deep tumor

--pT2a: Tumor more than 5 cm in greatest dimension, superficial tumor

--pT2b: Tumor more than 5 cm in greatest dimension, deep tumor

Regional Lymph Nodes (pN) (notes J and K)

--pNX: Regional lymph nodes cannot be assessed

--pN0: No regional lymph node metastasis

--pN1: Regional lymph node metastasis

Specify: Number examined:--

Number positive:--

Distant Metastasis (pM) (note J)

--Not applicable

--pM1: Distant metastasis

* Specify site(s), if known:--

* Additional Pathologic Findings

* Specify:--

Ancillary Studies

Immunohistochemistry

Specify:--

--Not performed

Cytogenetics

Specify:--

--Not performed

Molecular Pathology

Specify:--

--Not performed

Preresection Treatment (select all that apply)

--No therapy

--Chemotherapy performed

--Radiation therapy performed

--Therapy performed, type not specified

--Unknown

Treatment Effect (note G)

--Not identified

--Present

* Specify percentage of viable tumor:-- %

--Cannot be determined

* Comment(s):--

EXPLANATORY NOTES

A: Tissue Processing.--

Fixation

Tissue specimens from soft tissue tumors optimally are received fresh and unfixed because of the importance of ancillary studies, such as cytogenetics, which require fresh tissue.

Tissue Submission for Histologic Evaluation

One section per centimeter of maximum dimension is usually recommended, although fewer sections per centimeter are needed for very large tumors, especially if they are homogeneous. Tumors known to be high grade from a previous biopsy do not require as many sections as those that were previously diagnosed as low grade because documentation of a high-grade component will change stage and prognosis in the latter case. Sections should be taken of grossly heterogeneous areas, and there is no need to submit more than 1 section of necrotic tumor (always with a transition to viable tumor). Occasionally, gross pathology can be misleading, and areas that appear to be grossly necrotic may actually be myxoid or edematous. When this happens, additional sections of these areas should be submitted for histologic examination. When estimates of gross necrosis exceed those of histologic necrosis, the greater percentage of necrosis should be recorded on the surgical pathology report. In general, most tumors require 12 sections or fewer, excluding margins. Tumors with greater areas of heterogeneity may need to be sampled more thoroughly.

Fresh tissue for special studies should be submitted at the time the specimen is received. Note that classification of many subtypes of sarcoma is not dependent on special studies, such as cytogenetics or molecular genetics, but frozen tissue may be needed for patients to enter into treatment protocols. Discretion should be used in triaging tissue from sarcomas. Adequate tissue should be submitted for conventional light microscopy before tissue has been taken for cytogenetics, electron microscopy, or molecular analysis.

Molecular Studies

It is important to snap freeze a small portion of tissue whenever possible. This tissue can be used for a variety of molecular analyses for tumor-specific molecular translocations (see Table 1) that help in classifying soft tissue tumors. (2,3) In addition, treatment protocols increasingly require fresh tissue for correlative studies. Approximately 1 [cm.sup.3] of fresh tissue (less is acceptable for small specimens, including core biopsies) should be cut into small, 0.2-cm fragments, reserving sufficient tissue for histologic examination. This frozen tissue should ideally be stored at -70 [degrees]C and can be shipped on dry ice to facilities that perform molecular analysis.

B: Tumor Size.--In cases of nonexcisional biopsy (eg, core biopsy, incisional biopsy) the tumor size cannot be determined on pathologic grounds; therefore, imaging data (computed tomography [CT], magnetic resonance imaging [MRI], etc) can be used instead.

C: Histologic Classification.--

Intraoperative Consultation

Histologic classification of soft tissue tumors is sufficiently complex that, in many cases, it is unreasonable to expect a precise classification of these tumors based on an intraoperative consultation. A complete understanding of the surgeon's treatment algorithm is recommended before rendering a frozen section diagnosis. Intraoperative consultation is useful in assessing whether lesional tissue is present and in constructing a differential diagnosis that can direct the proper triage of tissue for flow cytometry (lymphoma), electron microscopy, and molecular studies and cytogenetics. Tissue triage optimally is performed at the time of frozen section. In many cases, it is important that a portion of tissue be submitted for ancillary studies, even from fine-needle aspiration (FNA) and core needle biopsy specimens, after sufficient tissue has been submitted for histologic evaluation.

Tumor Classification From Biopsies

It is not always possible to classify soft tissue tumors precisely based on biopsy material, especially FNA and core needle biopsy specimens. Although pathologists should make every attempt to classify lesions in small biopsy specimens, on occasion, stratification into very basic diagnostic categories, such as lymphoma, carcinoma, melanoma, and sarcoma, is all that is possible. In some cases, precise classification is only possible in open biopsies or resection specimens.

World Health Organization Classification of Tumors

Classification of tumors should be made according to the World Health Organization (WHO) classification of soft tissue tumors listed below. (4) As part of the latest WHO classification of soft tissue tumors, a recommendation was made to divide tumors into 4 categories: benign, intermediate (locally aggressive), intermediate (rarely metastasizing), and malignant.

WHO Classification of Soft Tissue Tumors of Intermediate Malignant Potential and Malignant Soft Tissue Tumors
Adipocytic Tumors

Intermediate (locally aggressive)
A typical lipomatous tumor/well-differentiated liposarcoma

Malignant
Dedifferentiated liposarcoma
Myxoid/round cell liposarcoma
Pleomorphic liposarcoma
Mixed-type liposarcoma
Liposarcoma, not otherwise specified

Fibroblastic/Myofibroblastic Tumors

Intermediate (locally aggressive)
Superficial fibromatoses (palmar/plantar)
Desmoid-type fibromatoses
Lipofibromatosis

Intermediate (rarely metastasizing)
Solitary fibrous tumor and hemangiopericytoma (including lipomatous
hemangiopericytoma)
Inflammatory myofibroblastic tumor
Low-grade myofibroblastic sarcoma
Myxoinflammatory fibroblastic sarcoma
Infantile fibrosarcoma

Malignant
Adult fibrosarcoma
Myxofibrosarcoma
Low-grade fibromyxoid sarcoma/hyalinizing spindle cell tumor
Sclerosing epithelioid fibrosarcoma

So-called Fibrohistiocytic Tumors

Intermediate (rarely metastasizing)
Plexiform fibrohistiocytic tumor
Giant cell tumor of soft tissues

Malignant
Pleomorphic malignant fibrous histiocytoma (MFH)/undifferentiated
pleomorphic sarcoma
Giant cell MFH/undifferentiated pleomorphic sarcoma with giant cells
Inflammatory MFH/undifferentiated pleomorphic sarcoma with prominent
inflammation

Smooth Muscle Tumors

Malignant
Leiomyosarcoma

Skeletal Muscle Tumors

Malignant
Embryonal rhabdomyosarcoma (including spindle cell, botryoid,
anaplastic)
Alveolar rhabdomyosarcoma (including solid, anaplastic)
Pleomorphic rhabdomyosarcoma

Vascular Tumors

Intermediate (locally aggressive)
Kaposiform hemangioendothelioma *
Intermediate (rarely metastasizing)
Retiform hemangioendothelioma
Papillary intralymphatic angioendothelioma
Composite hemangioendothelioma

Malignant
Epithelioid hemangioendothelioma
Angiosarcoma of soft tissue

Tumors of Peripheral Nerves

Malignant
Malignant peripheral nerve sheath tumor
Epithelioid malignant peripheral nerve sheath tumor

Chondro-osseous Tumors

Malignant
Mesenchymal chondrosarcoma
Extraskeletal osteosarcoma

Tumors of Uncertain Differentiation

Intermediate (rarely metastasizing)
Angiomatoid fibrous histiocytoma
Ossifying fibromyxoid tumor (including atypical/malignant)
Mixed tumor/myoepithelioma/parachordoma

Malignant
Synovial sarcoma
Epithelioid sarcoma
Alveolar soft part sarcoma
Clear cell sarcoma of soft tissue
Extraskeletal myxoid chondrosarcoma (chordoid type)
Primitive neuroectodermal tumor (PNET)/extraskeletal Ewing tumor
Peripheral primitive neuroectodermal tumor (pPNET)
Extraskeletal Ewing tumor
Desmoplastic small round cell tumor
Extrarenal rhabdoid tumor
Malignant mesenchymoma
Neoplasms with perivascular epithelioid cell differentiation (PEComa)
Clear cell myomelanocytic tumor
Intimal sarcoma

* Since the last edition of the WHO classification, 2 cases of
well-documented regional metastasis of kaposiform hemangioendothelioma
have been reported, (5) raising the issue of whether or not kaposiform
hemangioendothelioma might be more appropriately included in the
category of "intermediate (rarely metastasizing)" instead of
"intermediate (locally aggressive)." This will undoubtedly be addressed
in the next WHO classification of tumors of soft tissue.


D: Grading.--Unlike with other organ systems, the staging of soft tissue sarcomas is largely determined by grade. Unfortunately, there is no scheme generally agreed on for grading soft tissue tumors. (6) The most widely used soft tissue grading systems are the French Federation of Cancer Centers Sarcoma Group (FNCLCC) and the National Cancer Institute (NCI) systems. (7,8) Both systems have 3 grades, based on mitotic activity, necrosis, and differentiation, and are highly correlated with prognosis. (9) However, in addition to these criteria, the NCI system requires the quantification of cellularity and pleomorphism for certain subtypes of sarcomas, which is difficult to determine objectively. The FNCLCC system is easier to use, in our opinion, and it may be slightly better at predicting prognosis than the NCI system. (9) Other systems with 2 or 4 grades also have been used. The 7th edition of the AJCC Cancer Staging Manual (10) adopted the FNCLCC grading system. The revision of the American Joint Committee on Cancer (AJCC) staging system incorporates a 3-tiered grading system; however, grade 1 and grades 2 to 3 (effectively low and high) are used for staging groups. Accurate grading requires an adequate sample of tissue, which is not always available from FNA or core needle biopsy or in tumors previously treated with radiation or chemotherapy. However, given the importance of grade in staging and treatment, efforts to separate sarcomas on the basis of needle biopsies into at least 2 tiers (ie, low and high grades) is encouraged. In many instances the histologic type of the sarcoma will readily permit this distinction (ie, Ewing sarcoma/PNET, pleomorphic liposarcoma), whereas in less-obvious instances the difficulty of assigning grade should be noted. In general, multiple needle core biopsies exhibiting a high-grade sarcoma can be regarded as high grade because the probability of subsequent downgrading is remote, but limited core biopsies of low-grade sarcoma carry a risk of upgrading.

French Federation of Cancer Centers Sarcoma Group Grading

The FNCLCC grade is based on 3 parameters: differentiation, mitotic activity, and necrosis. Each of these parameters receives a score: differentiation (1 to 3), mitotic activity (1 to 3), and necrosis (0 to 2). The scores are summed to produce a grade.

Grade 1: 2 or 3

Grade 2: 4 or 5

Grade 3: 6 to 8

Differentiation: Tumor differentiation is scored as follows (see Table 2).

Score 1: Sarcomas closely resembling normal, adult mesenchymal tissue

Score 2: Sarcomas of certain histologic type

Score 3: Synovial sarcomas, embryonal sarcomas, undifferentiated sarcomas, and sarcomas of doubtful tumor type

Tumor differentiation is the most problematic aspect of the FNCLCC system. Its use is subjective and does not include every subtype of sarcoma. Nevertheless, it is an integral part of the system, and an attempt should be made to assign a differentiation score.

Mitosis Count: The count is made in the most mitotically active area in 10 successive HPFs (1 HPF X400 = 0.1734 [mm.sup.2]) (use the X40 objective).

Score 1: 0 to 9 mitoses per 10 HPF

Score 2: 10 to 19 mitoses per 10 HPF

Score 3: 20 or more mitoses per 10 HPF

Tumor Necrosis: Determined on histologic sections.

Score 0: No tumor necrosis

Score 1: Less than or equal to 50% tumor necrosis

Score 2: More than 50% tumor necrosis

TNM Grading

The 7th edition of the AJCC/UICC staging system for soft tissue tumors recommends the FNCLCC 3-grade system but effectively collapses into high grade and low grade. (10,11) This means that FNCLCC grade 2 tumors are considered high grade for the purposes of stage grouping.

E: Margins.--It has been recommended that for all margins less than 2 cm, the distance of the tumor from the margin be reported in centimeters. (12) However, there is a lack of agreement on this issue. We recommend specifying the location of all margins that are less than 2 cm and the distance of the closest margin that is less than 2 cm. Margins from soft tissue tumors should be taken as perpendicular sections, if possible. If bones are present in the specimen and are not involved by tumor, or the tumor is greater than 2 cm from the margin, the marrow can be scooped out and submitted as a margin.

F: Lymph-Vascular Invasion.--Lymph-vascular invasion (LVI) indicates whether microscopic lymph-vascular invasion is identified. Lymph-vascular invasion includes lymphatic invasion, vascular invasion, or lymph-vascular invasion. By AJCC/UICC convention, LVI does not affect the T category, which indicates the local extent of tumor, unless specifically included in the definition of a T category.

G: Response to Chemotherapy/Radiation Therapy Effect.--Although agreement has not been reached about measuring the effect of preoperative (neoadjuvant) chemotherapy/radiation therapy in soft tissue tumors, an attempt should be made to quantify these effects, especially in the research setting. Therapy response is expressed as a percentage of the total tumor area that is viable. Nonliquefied tumor tissue from a cross-section through the longest axis of the tumor should be sampled. At least 1 section of necrotic tumor (always with a transition to viable tumor) should be sampled to verify the gross impression of necrosis. Nonsampled necrotic areas should be included in the estimate of necrosis and the percentage of tumor necrosis reported. The gross appearance can be misleading, and areas that appear grossly necrotic may actually be myxoid or edematous. Additional sections from these areas should be submitted for histologic examination. When estimates of gross necrosis exceed those of histologic necrosis, the greater percentage of necrosis should be recorded on the surgical pathology report.

H: Definition of Procedures.--The following is a list of guidelines to be used in defining what type of procedure has been performed.

Intralesional Resection: Leaving gross or microscopic tumor behind. Partial debulking or curettage are examples or when microscopic tumor is left at the margin unintentionally in an attempted marginal resection.

Marginal Resection: Removing the tumor and its pseudocapsule with a relatively small amount of adjacent tissue. There is no gross tumor at the margin; however, there is a high likelihood that microscopic tumor is present. If microscopic disease is identified at the margin, then it is an intralesional resection. Note that occasionally a surgeon will perform an excisional biopsy, which effectively accomplishes the same thing as a marginal resection.

Wide Resection: An intracompartmental resection. The tumor is removed with pseudocapsule and a cuff of normal tissue surrounding the neoplasm but without the complete removal of an entire muscle group, compartment, or bone.

Radical Resection: The removal of an entire soft tissue compartment (for example, anterior compartment of the thigh, the quadriceps) or bone, or the excision of the adjacent muscle groups if the tumor is extracompartmental.

I: Histologic Classification of Treated Lesions.--Because of extensive treatment effects, such as necrosis, fibrosis, and chemotherapy-induced and radiation-induced pleomorphism, it may not be possible to classify some lesions when either they were never biopsied or the biopsy was insufficient for a precise diagnosis.

J: TNM and Stage Groupings.--The TNM staging system for soft tissue tumors of the AJCC and UICC is recommended. (10,11) The staging system applies to all soft tissue sarcomas, except Kaposi sarcoma, gastrointestinal stromal tumors, fibromatosis (desmoid tumor), and infantile fibrosarcoma. In addition, sarcomas arising within the confines of the dura mater, including the brain, and sarcomas arising in parenchymatous organs and from hollow viscera are not optimally staged by this system.

Pathologic (pTNM) staging consists of the removal and pathologic evaluation of the primary tumor and clinical/radiologic evaluation for regional and distant metastases. In circumstances in which it is not possible to obtain accurate measurements of the excised primary sarcoma specimen, it is acceptable to use radiologic assessment of tumor size to assign a pT category. In examining the primary tumor, the pathologist should subclassify the lesion and assign a histopathologic grade.

Definition of pT

Although size currently is designated within the TNM system as 5 cm or smaller versus larger than 5 cm, particular emphasis should be placed on providing size measurements. Size should be regarded as a continuous variable, with 5 cm as merely an arbitrary division that makes it possible to dichotomize patient populations.

Depth

Depth is evaluated relative to the investing fascia of the extremity and trunk. "Superficial" is defined as lack of any involvement of the superficial investing muscular fascia in extremity or trunk lesions. For staging, all retroperitoneal and visceral lesions are considered to be "deep lesions."

Depth is also an independent variable and is defined as follows.

A. Superficial

1. Tumor is located entirely in the subcutaneous tissues without any involvement of the muscular fascia. In these cases, pretreatment imaging studies demonstrate a subcutaneous tumor without involvement of muscle, and excisional biopsy pathology specimen demonstrate a tumor located within the subcutaneous tissues without invasion into fascia (adopted from the 7th edition of the AJCC Cancer Staging Manual (10)).

B. Deep

1. Tumor is located partly or completely within 1 or more muscle groups within the extremity. Deep tumors may extend through the muscular fascia into the subcutaneous tissues or even to the skin, but the critical criterion is location of any portion of the tumor within the muscular compartments of the extremity or invasion of the muscular fascia. In these cases, pretreatment imaging studies demonstrate a tumor located completely or partly within the muscular compartments of the extremity. Finally, on pathologic evaluation, any tumor that is superficial to the muscular fascia but invades the fascia is considered deep (adopted from the 7th edition of the AJCC Cancer Staging Manual (10)).

2. All intraperitoneal visceral lesions, retroperitoneal lesions, intrathoracic lesions, and most head and neck tumors are considered deep.

C. Depth is evaluated in relation to tumor size (T)

1. Tumor 5 cm or less: T1a = superficial; T1b = deep.

2. Tumor greater than 5 cm: T2a = superficial; T2b = deep.

Regional Lymph Nodes (pN)

Nodal involvement is rare in adult soft tissue sarcomas but, when present, has a very poor prognosis. N1 disease is classified as stage III. Patients whose nodal status is not determined to be positive for tumor, either clinically or pathologically, should be designated as N0.

Restaging of Recurrent Tumors

The same staging should be used when a patient requires restaging of sarcoma recurrence. Such reports should specify whether patients have primary lesions or lesions that were previously treated and have subsequently recurred. Reporting of possible etiologic factors, such as radiation exposure and inherited or genetic syndromes, is encouraged. Appropriate workup for recurrent sarcoma usually includes cross-sectional imaging (CT scan or MRI scan) of the tumor, a CT scan of the chest, and a tissue biopsy to confirm diagnosis before initiation of therapy.

TNM Descriptors

For identification of special cases of TNM or pTNM classifications, the "m" suffix and the "y" and "r" prefixes are used. Although they do not affect the stage grouping, they indicate cases needing separate analysis.

The "m" suffix indicates the presence of multiple primary tumors in a single site and is recorded in parentheses: pT(m)NM.

The "y" prefix indicates those cases in which classification is performed during or following initial multimodality therapy (ie, neoadjuvant chemotherapy, radiation therapy, or both chemotherapy and radiation therapy). The cTNM or pTNM category is identified by a "y" prefix. The ycTNM or ypTNM categorizes the extent of tumor actually present at the time of that examination. The "y" categorization is not an estimate of tumor before multimodality therapy (ie, before initiation of neoadjuvant therapy).

The "r" prefix indicates a recurrent tumor when staged after a documented disease-free interval: rTNM.

T Category Considerations

Superficial tumor is located exclusively above the superficial fascia without invasion of the fascia; deep tumor is located either exclusively beneath the superficial fascia or superficial to the fascia with invasion of, or through, the fascia. Retroperitoneal, mediastinal, and pelvic sarcomas are classified as deep tumors.

N Category Considerations

Presence of positive nodes (N1) is considered stage III.

M Category Considerations

pMX and pM0 (no distant metastasis) are no longer checklist options because the use of pMX provides no meaningful information to the clinician or cancer registrar and, at times, may create confusion in tumor staging.

Additional Descriptors

Residual Tumor (R)

Tumor remaining in a patient after therapy with curative intent (eg, surgical resection for cure) is categorized by a system known as R classification, shown below.

RX Presence of residual tumor cannot be assessed

R0 No residual tumor

R1 Microscopic residual tumor

R2 Macroscopic residual tumor

For the surgeon, the R classification may be useful to indicate the known or assumed status of the completeness of a surgical excision. For the pathologist, the R classification is relevant to the status of the margins of a surgical resection specimen. That is, tumor involving the resection margin on pathologic examination may be assumed to correspond to residual tumor in the patient and may be classified as macroscopic or microscopic according to the findings at the specimen margin(s).

K: Lymph Nodes.--With the exception of epithelioid sarcoma and clear cell sarcoma of soft parts, regional lymph node metastasis is uncommon in adult soft tissue sarcomas. Nodes are not sampled routinely, and it usually is not necessary to exhaustively search for nodes. When present, regional lymph node metastasis has prognostic importance and should be reported. The 7th edition of the AJCC Cancer Manual recommends that N1 M0 disease to be regarded as stage III, rather than stage IV, disease. (10)

References

(1.) Qualman SJ, Bowen J, Parham DM, Branton PA, Meyer WH. Protocol for the examination of specimens from patients (children and young adults) with rhabdomyosarcoma. Arch Pathol Lab Med. 2003;127(10):1290-1297.

(2.) Ladanyi M, Bridge JA. Contribution of molecular genetic data to the classification of sarcomas. Hum Pathol. 2000;31(5):532-538.

(3.) Tomescu O, Barr FG. Chromosomal translocations in sarcomas: prospects for therapy. Trends Mol Med. 2001;7(12):554-559.

(4.) Fletcher CDM, Unni KK, Mertens F, eds. Pathology and Genetics of Tumours of Soft Tissue and Bone. Lyon, France: IARC Press; 2002. World Health Organization Classification of Tumours; vol 4.

(5.) Lyons LL, North PE, Mac-Moune Lai F, Stoler MH, Folpe AL, Weiss SW. Kaposiform hemangioendothelioma: a study of 33 cases emphasizing its pathologic, immunophenotypic, and biologic uniqueness from juvenile hemangioma. Am J Surg Pathol. 2004;28(5):559-568.

(6.) Oliveira AM, Nascimento AG. Grading in soft tissue tumors: principles and problems. Skeletal Radiol. 2001;30(10):543-559.

(7.) Coindre JM, Trojani M, Contesso G, et al. Reproducibility of a histopathologic grading system for adult soft tissue sarcoma. Cancer. 1986; 58(2):306-309.

(8.) Costa J, Wesley RA, Glatstein E, Rosenberg SA. The grading of soft tissue sarcomas: results of a clinicohistopathologic correlation in a series of 163 cases. Cancer. 1984;53(3):530-541.

(9.) Guillou L, Coindre JM, Bonichon F, et al. Comparative study of the National Cancer Institute and French Federation of Cancer Centers Sarcoma Group grading systems in a population of 410 adult patients with soft tissue sarcoma. J Clin Oncol. 1997;15(1):350-362.

(10.) Edge SE, Byrd DR, Compton CC, Fritz AG, Greene FL, Trotti A, eds. AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer; 2009.

(11.) Sobin LH, Gospodarowicz M, Wittekind Ch, eds. TNM Classification of Malignant Tumours. 7th ed. New York, NY: Wiley-Blackwell; 2009.

(12.) Association of Directors of Anatomic and Surgical Pathology. Recommendations for the reporting of soft tissue sarcomas. Mod Pathol. 1998;11(12):1257-1261.

Brian P. Rubin, MD, PhD; Kumarasen Cooper, MBChB; Christopher D. M. Fletcher, MD, FRCPath; Andrew L. Folpe, MD; Francis H. Gannon, MD; Jennifer L. Hunt, MD; Alexander J. Lazar, MD, PhD; Anthony G. Montag, MD; Terrance D. Peabody, MD; Raphael E. Pollock, MD, PhD; John D. Reith, MD; Stephen J. Qualman, MD ([dagger]); Andrew E. Rosenberg, MD; Sharon W. Weiss, MD; Thomas Krausz, MD, FRCPath; for the Members of the Cancer Committee, College of American Pathologists

([dagger]) Deceased.

Accepted for publication December 11, 2009.

We dedicate this work to our esteemed and beloved colleague, Steve Qualman, MD, who passed away during the writing of this document. Steve was a tireless investigator, academic leader, and compassionate physician who made significant and long-lasting contributions to our understanding of the pathobiology of sarcomas. He established the Biopathology Center (BPC) at Columbus Children's Hospital (Columbus, Ohio), which currently houses more than 1,000,000 specimens and is an integral component of the Cooperative Human Tissue Network (CHTN) critical for translational research. Throughout the years, he was an integral part of, and force behind, the Intergroup Rhabdomyosarcoma Studies, which produced the most comprehensive and authoritative work on this disease. His expertise, reflected in this body of work, has helped countless pathologists, clinicians, and pediatric patients worldwide. Even though Steve is no longer with us, his legacy lives on.

From the Departments of Anatomic Pathology and Molecular Genetics, Cleveland Clinic, Lerner Research Institute and Taussig Cancer Center, Cleveland, Ohio (Dr Rubin);the Department of Pathology, University of Vermont and Fletcher Allen Health Care, Burlington, Vermont (Dr Cooper);the Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts (Dr Fletcher); the Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota (Dr Folpe); the Department of Pathology, Baylor College of Medicine, Houston, Texas (Dr Gannon); the Department of Pathology, Massachusetts General Hospital, Boston (Drs Hunt and Rosenberg);the Departments of Pathology (Dr Lazar) and Surgical Oncology (Dr Pollock), Sarcoma Research Center, The University of Texas M. D. Anderson Cancer Center, Houston;the Departments of Pathology (Drs Montag and Krausz) and Orthopaedic Surgery (Dr Peabody), University of Chicago Medical Center, Chicago, Illinois; the Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville (Dr Reith); the Department of Laboratory Medicine, Children's Hospital, Columbus, Ohio (Dr Qualman); and the Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia (Dr Weiss).

The authors have no relevant financial interest in the products or companies described in this article.

Reprints: Brian P. Rubin, MD, PhD, Department of Anatomic Pathology, L25, Cleveland Clinic, 9500 Euclid Ave, Cleveland, Ohio 44195 (e-mail: rubinb2@ccf.org).
Table 1. Characteristic Cytogenetic and Molecular Events of Soft
Tissue Tumors

            Histologic Type                   Cytogenetic Events

Alveolar soft part sarcoma                t(X;17)(p11;q25)
Aneurysmal bone cyst                      t(16;17)q22;p13)
Angiomatoid fibrous histiocytoma          t(12;16)(q13;p11)
                                          t(12;22)(q13;q12)
                                          t(2;22)(q33;q12)
Extraskeletal myxoid chondrosarcoma       t(9;22)(q22;q12)
                                          t(9;17)(q22;q11)
                                          t(9;15)(q22;q21)
Clear cell sarcoma                        t(12;22)(q13;q12)
                                          t(2;22(q33;q12)
Desmoplastic small round cell tumor       t(11;22)(p13;q12)
Dermatofibrosarcoma protuberans           Ring form of chromosomes 17
                                            and 22
                                          t(17;22)(q21;q13)
Ewing sarcoma/PNET                        t(11;22)(q24;q12)
                                          t(21;22)(q12;q12)
                                          t(2;22)(q33;q12)
                                          t(7;22)(p22;q12)
                                          t(17;22)(q12;q12)
                                          inv(22)(q12q12)
                                          t(16;21)(p11;q22)
Fibrosarcoma, infantile                   t(12;15)(p13;q26)
                                          Trisomies 8, 11, 17, and 20
Inflammatory myofibroblastic tumor        t(1;2)(q22;p23)
                                          t(2;19)(p23;p13)
                                          t(2;17)(p23;q23)
                                          t(2;2)(p23;q13)
Leiomyosarcoma                            Complex with frequent
                                            deletion of 1p
Liposarcoma
  Well-differentiated                     Ring form of chromosome 12
  Myxoid/round cell                       t(12;16)(q13;p11)
                                          t(12;22)(q13;q12)
  Pleomorphic                             Complex
Low-grade fibromyxoid sarcoma             t(7;16)(q33;p11)
Malignant peripheral nerve sheath tumor   Complex
Myxofibrosarcoma (myxoid MFH)             Ring form of chromosome 12
Rhabdoid tumor                            Deletion of 22q
Rhabdomyosarcoma
  Alveolar                                t(2;13)(q35;q14)
                                          t(1;13)(p36;q14), double
                                            minutes
                                          t(2;2)(q35;p23)
  Embryonal                               Trisomies 2q, 8 and 20
Synovial sarcoma
  Monophasic                              t(X;18)(p11;q11)
  Biphasic                                t(X;18)(p11;q11)

            Histologic Type                    Molecular Events

Alveolar soft part sarcoma                TFE3-ASPL fusion
Aneurysmal bone cyst                      CDH11-USP6 fusion
Angiomatoid fibrous histiocytoma          FUS-ATF1 fusion
                                          EWSR1-ATF1 fusion
                                          EWSR1-CREB1 fusion
Extraskeletal myxoid chondrosarcoma       EWS-NR4A3 fusion
                                          TAF2N-NR4A3 fusion
                                          TCF12-NR4A3 fusion
Clear cell sarcoma                        EWSR1-ATF1 fusion
                                          EWSR1-CREB1 fusion
Desmoplastic small round cell tumor       EWSR1-WT1 fusion
Dermatofibrosarcoma protuberans           COL1A1-PDGFB fusion
                                          COL1A1-PDGFB fusion
Ewing sarcoma/PNET                        EWSR1-FLI1 fusion
                                          EWSR1-ERG fusion
                                          EWSR1-FEV fusion
                                          EWSR1-ETV1 fusion
                                          EWSR1-E1AF fusion
                                          EWSR1-ZSG fusion
                                          FUS-ERG fusion
Fibrosarcoma, infantile                   ETV6-NTRK3 fusion
Inflammatory myofibroblastic tumor        TPM3-ALK fusion
                                          TPM4-ALK fusion
                                          CLTC-ALK fusion
                                          RANB2-ALK fusion
Leiomyosarcoma
Liposarcoma
  Well-differentiated                     Amplification of MDM2,
                                            CDK4, and others
  Myxoid/round cell                       TLS-DDIT3 fusion
                                          EWSR1-DDIT3 fusion
  Pleomorphic
Low-grade fibromyxoid sarcoma             FUS-CREB3L2 fusion
Malignant peripheral nerve sheath tumor
Myxofibrosarcoma (myxoid MFH)
Rhabdoid tumor                            INI1 inactivation
Rhabdomyosarcoma
  Alveolar                                PAX3-FOXO1A fusion
                                          PAX7-FOXO1A fusion
                                          PAX3-NCOA1 fusion PAX3-AFX
                                            fusion
  Embryonal                               Loss of heterozygosity at
                                            11p15
Synovial sarcoma
  Monophasic                              SS18-SSX1, SS18-SSX2 or
                                            SS18-SSX4 fusion
  Biphasic                                Predominantly SS18-SSX1
                                            fusion

Abbreviations: MFH, malignant fibrous histiocytoma; PNET, primitive
neuroectodermal tumor.

Table 2. Tumor Differentiation Score According to
Histologic Type in the Updated Version of the French
Federation of Cancer Centers Sarcoma Group System of
Tumor Differentiation

Histologic Type                                           Score

Well-differentiated liposarcoma                             1
Myxoid liposarcoma                                          2
Round cell liposarcoma                                      3
Pleomorphic liposarcoma                                     3
Dedifferentiated liposarcoma                                3
Fibrosarcoma                                                2
Myxofibrosarcoma MFH                                        2
Typical storiform MFH (sarcoma, NOS)                        3
MFH, pleomorphic type (patternless pleomorphic
  sarcoma)                                                  3
Giant cell and inflammatory MFH (pleomorphic
  sarcoma, NOS, with giant cells or inflammatory cells)     3
Well-differentiated leiomyosarcoma                          1
Conventional leiomyosarcoma                                 2
Poorly differentiated/pleomorphic/epithelioid
  leiomyosarcoma                                            3
Biphasic/monophasic synovial sarcoma                        3
Poorly differentiated synovial sarcoma                      3
Pleomorphic rhabdomyosarcoma                                3
Mesenchymal chondrosarcoma                                  3
Extraskeletal osteosarcoma                                  3
Ewing sarcoma/primitive neuroectodermal tumor               3
Malignant rhabdoid tumor                                    3
Undifferentiated sarcoma                                    3

Note: Grading of malignant peripheral nerve sheath tumor, embryonal
and alveolar rhabdomyosarcoma, angiosarcoma, extraskeletal myxoid
chondrosarcoma, alveolar soft part sarcoma, clear cell sarcoma, and
epithelioid sarcoma is not recommended.4 Modified from Guillou et
al, (9) with permission from the American Society of Clinical
Oncology.

Abbreviations: MFH, malignant fibrous histiocytoma; NOS, not
otherwise specified.

Stage Groupings

Stage IA    T1a     N0      NX   M0   G1      Low
            T1b     N0      NX   M0   G1      Low
Stage IB    T2a     N0      NX   M0   G1      Low
            T2b     N0      NX   M0   G1      Low
Stage IIA   T1a     N0      NX   M0   G2,G3   High
            T1b     N0      NX   M0   G2,G3   High
Stage IIB   T2a     N0      NX   M0   G2      High
            T2b     N0      NX   M0   G2      High
Stage III   T2a     N0      NX   M0   G3      High
            T2b     N0      NX   M0   G3      High
            Any T   N1           M0   Any G   High or Low
Stage IV    Any T   Any N        M1   Any G   High or Low
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Title Annotation:CAP Laboratory Improvement Programs
Author:Rubin, Brian P.; Cooper, Kumarasen; Fletcher, Christopher D.M.; Folpe, Andrew L.; Gannon, Francis H.
Publication:Archives of Pathology & Laboratory Medicine
Article Type:Report
Geographic Code:1USA
Date:Apr 1, 2010
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