Cutaneous granular cell tumor on the arm in a middle-aged man.
Granular Cell Tumor (GCT) is a usually benign neoplasm that is most often found in the head and neck region, usually in the oropharynx. Ever since it was first described by Abrikossoff in the 1920s, (1) there had been much debate about the tissue origin of GCT. However, it wasn't until the advent of immunohistochemistry and advanced molecular techniques that dermatologists realized that GCT are closer in origin to Schwann cells than they are to skeletal muscle. Clinically, GCT cannot be distinguished from many other neoplasms, such as neurofibroma or leiomyoma, but under microscopic examination it can readily be identified by the extensive cytoplasmic granules in the proliferating cells. While the vast majority of GCTs are benign, there is a small minority, less than two percent, that may be malignant.
A 44-year-old Caucasian male sought treatment for a growing nodule of his right arm for the past nine months (Figure 1). The patient said there was no inciting trauma to the area, and he had never had anything similar. There had been no bleeding or discharge, and the tumor was non-pruritic and non-tender. He denied fever, chills, night sweats, chest pain, dyspnea, or weight loss. The patient had no significant past medical history and no previous skin cancers, but he had significant sun exposure in the past. The patient was a current smoker, but he did not take any medications or have any allergies.
On physical examination, there was an 11 mm diameter firm nodule on the proximal lateral right arm with mild overlying erythema. The lesion was non-tender and not warm to touch. Range of motion in the adjacent joints was full, and there was no axillary or supratrochlear lymphadenopathy.
Gross microscopic view using hematoxylin and eosin stain showed groups of tumor cells separated by bands of connective tissue (Figure 2). At higher magnification, there were large ovoid cells with an abundant eosinophilic granular cytoplasm (Figure 3). The nuclei were small and without abnormal features. Excision of the tumor with 5 mm margins was performed to minimize the chance of recurrence. While the tumor appeared completely excised it did extend close to the borders. The patient was asked to follow up in three months or sooner if there were signs of recurrence. At the six-month follow up, the patient showed no signs of recurrence, and he did not voice any complaints.
GCT is a rare soft tissue tumor that often presents in the head and neck region. Most GCTs are located in the oral mucosa, especially on the tongue. They can also be found along the GI tract (2) and on the breast. (3) It is thought that GCT neoplasms are of neural origin, as many have histologic and protein expression characteristics similar to Schwann cells in the peripheral nervous system. While the great majority of GCTs are benign neoplasms, roughly two percent of them can be malignant. (4) However, without proper margins in the excision, recurrence of benign GCT occurs thirty percent of the time.
While GCTs can be found in both sexes, epidemiological evidence suggests they occur in women between 1 and 1.5 times more often than in men, and people of African ancestry tend to have them more commonly. (5) They usually appear in the third to fifth decade of life.
On clinical examination, GCTs can present as red to brown to flesh colored, and they are normally excised before they are larger than two cm in diameter. (6) They are firm and can have ill-defined margins, raising initial concern for malignancy. Microscopic examination is usually limited to HE staining, but specific immunohistochemical markers can be useful, such as Vimentin, Neuron Specific Enolase, and S-100 Protein. (7) On HE stain, large cells are seen with numerous cytoplasmic granules. Granules may be small and regular or large eosinophilic PAS+ droplets. Often there is epithelial hyperplasia near the site of the GCT. As with most histologic specimens, presence of the following increases likelihood of malignancy: necrosis, spindling, vesicular nuclei with large nucleoli, increased mitotic activity, high nuclear to cytoplasmic ratio, and pleomorphism. (8) Wide local excision is the treatment of choice for benign GCT. (4)
(1.) Abrikossoff, A. Myomas Originating from Transversely Striated Voluntary Musculature. Virchows Arch Pathol Anat. 1926; 260: 215-233.
(2.) Cordoba A, Manrique M, Zozaya E, et al. Granular-Cell Tumor of the Esophagus: Report of a Case with a Cytologic Diagnosis Based on Esophageal Brushing. Diagn Cytopathol. 1998; 19:455-457.
(3.) DeMay RM, Kay S. Granular Cell Tumor of the Breast. Pathol Ann. 1984; 19: 121-148.
(4.) Enzinger RM, Weiss SW. Granular Cell Tumor. In: Soft Tissue Tumors, 3rd ed. St Louis: Mosby; 1995; 864-875.
(5.) Vance SF III, Hudson RP Jr. Granular Cell Myoblastoma: Clinicopathologic Study of Forty-Two Patients. Am J Clin Pathol. 1969; 52:208-211.
(6.) Lack EE, Worsham GF, Callihan MD, et al. Granular Cell Tumor: A Clinicopathologic Study of 110 Patients. J Surg Oncol. 1980; 13:301-316.
(7.) Ordonez NG, Mackay B. Granular Cell Tumor: A Review of the Pathology and Histogenesis. Ultrastruct Pathol. 1999; 23:207-222.
(8.) Fanburg-Smith JC, Meis-Kindblom JM, Fante R, et al. Malignant Granular Cell Tumor of Soft Tissue: Diagnostic Criteria and Clinicopathologic Correlation. Am J Surg Pathol. 1998; 22:779-794.
* All photo credits to Dr. Crandall and the Dermatology Department at Naval Medical Center San Diego.
ENS Kenneth A. Benson, LCDR Michael Crandall, MD
Mr. Benson is a fourth year medical student at Louisiana State University Health Sciences Center in Shreveport, LA. Dr. Crandall is affiliated with the Naval Medical Center, San Diego, CA.
US Navy Disclaimer: The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government. Drs. Benson and Crandall are military service members. This work was prepared as part of their official duties. Title 17, USC, § 105 provides that 'Copyright protection under this title is not available for any work of the United States Government.' Title 17, USC, § 101 defines a U.S. Government work as a work prepared by a military service member or employee of the U.S. Government as part of that person's official duties.
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|Author:||Benson, Kenneth A.; Crandall, Michael|
|Publication:||The Journal of the Louisiana State Medical Society|
|Date:||Nov 1, 2015|
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