Asymptomatic enlargement of the medial clavicle: report of five cases. (Case Report).

Abstract: Five middle-aged women presented with unexplained chronic swelling at the medial clavicle. None of the patients recalled a history of trauma and none experienced pain or other symptoms associated with the swelling. In all cases, suspicion of tumor prompted referral to an orthopedic oncologist; two cases were hiopsied before referral. Radiological studies demonstrated degenerative changes confined to the medial clavicle in three cases, exophytic overgrowth of the medial clavicle and adjacent manubrium in one case, and bilateral degenerative changes on both sides of the joint in one case. Prolonged follow-up supported the diagnosis of a benign, likely degenerative condition. These cases demonstrate the tendency for a variety of degenerative changes to manifest clinically as swelling at the medial clavicle. Inherent properties of the clavicle may predispose the medial clavicle to such changes. Recognition of this entity may prevent unnecessary testing or surgical biopsy of patients with this condition in the future. A thorough differential diagnosis of swelling at the medial clavicle is also presented.

**********

Isolated swelling at the medial clavicle occurring in the absence of preceding traumatic injury is rarely. encountered in clinical practice. (1) Diagnostic difficulty may arise from the limited experience of any individual in dealing with this unusual complaint. (2) The tendency for some benign clavicular conditions to appear aggressive radiographically may add to the difficulty. (2,3) Numerous reports of patients with benign clavicular lesions describe how a correct diagnosis was reached only after a battery of diagnostic tests or biopsy had been performed to rule out neoplasm. (2-6) Scant documentation of some benign conditions in the literature may contribute to the tendency to overlook these conditions. The senior author (GB), an orthopedic oncologist, has received in consultation a number of patients with asymptomatic enlargement of the medial clavicle (Fig. 1). Concern for neoplasm prompted referral to our service. Two cases were referred after biopsy was performed. The clinical and radiological feature s of five middle-aged women diagnosed with a painless, benign, likely degenerative condition affecting the medial clavicle are presented.

Discussion

The clavicle is a rare site for primary bone tumor. (2,7,8) Relatively few clavicular neoplasms are localized to the medial one-third of the bone. (2,8) The possibility of neoplasm should be considered in the differential diagnosis of an apparently aggressive clavicular mass, as the majority of neoplasms occurring in the clavicle are malignant. (3,7,8) A number of benign conditions may also cause a lesion at the medial clavicle. Some benign conditions are relatively common. (9) Physicians should carefully consider the differential diagnosis of a swelling at the medial clavicle before proceeding with an extensive workup to rule out malignancy (Table 1).

Patient 5 serves as an example of how a relatively common condition, osteoarthritis of the sternoclavicular joint, may manifest clinically as a swelling in the sternoclavicular area. This case demonstrates the need to first consider the differential diagnosis of an apparent swelling at the medial clavicle before biopsy. Features including chronicity and lack of symptoms are uncommon in patients presenting with tumor. (2) Biopsy could have been postponed or avoided if the opinion of an experienced musculoskeletal radiologist had been sought at the outset.

Patients 1 to 4 had a variety of unilateral degenerative changes. To varying degrees, clinical and radiographic features of these cases were consistent with two benign conditions, osteoarthritis of the sternoclavicular joint and condensing osteitis of the clavicle. A brief description of each condition follows and demonstrates these similarities and also highlights the differences between the cases and those previously described under these headings.

Osteoarthritis of the sternoclavicular joint is a common condition that becomes ubiquitous with advancing age. Kier et al (10) found moderate to severe radiographic evidence of sternoclavicular joint osteoarthritis in more than half of all patients older than 60 years of age. Bilateral disease is most common, but some reports describe a mild degree of asymmetry. (11) Isolated unilateral involvement has been described in a few reports, mostly of patients with a history of strenuous manual labor. (11) Whereas symptoms are typically absent in bilateral disease, pain and tenderness are usually prominent in unilateral cases. (11) Pain may lead to restriction of active shoulder movement to varying degrees. (11) Radiographic signs of osteoarthritis at the sternoclavicular joint include unevenness of the articular surface, osteophytes, subchondral sclerosis, and cystic changes on both sides of the joint surface. (10,12) Some reports note that the severity of clavicular involvement tends to exceed manubrial disease, b ut this has generally been an inconsistent finding. (11) Most patients with symptomatic sternoclavicular joint osteoarthritis improve spontaneously or with conservative therapy. (11)

Condensing osteitis of the clavicle is a rare idiopathic condition marked clinically by pain and radiographically by sclerosis and slight enlargement of the inferomedial clavicle. (4-6,13-15,21) Middle-aged women are usually affected, and most cases are unilateral. Bony sclerosis obliterates the marrow space at the clavicular head to varying degrees. Concomitant osteophyte formation at the inferomedial aspect of the clavicle (13,14) and overlying soft tissue swelling have also been described. (5) This condition may be differentiated radiographically from osteoarthritis by preservation of the joint space and lack of manubrial involvement. Most patients report pain exacerbated by arm movement and tenderness over the affected area. The natural history of this lesion may include normalization, stationary appearance, increased sclerosis, or progression to osteoarthritis of the sternoclavicular joint. (16) The latter observation has led some to propose that condensing osteitis of the clavicle reflects a pattern of degenerative change observed in early osteoarthritis. (16) Conservative treatment is generally recommended for patients with slight or no pain. If the diagnosis is uncertain and if pain is a significant feature, biopsy is recommended to confirm the benign nature of the lesion. (4)

As Patients 1 to 4 did not fit the classic description for any single condition, the preferred diagnosis was of a degenerative condition affecting the medial clavicle. A number of factors may predispose the head of the clavicle to degenerative changes. The sternoclavicular joint is the only synovial articulation between the upper extremity and the trunk. Motion at the sternoclavicular joint accompanies every arm movement and is important in contributing to abduction of the upper extremity. The sternoclavicular joint is therefore one of the most active joints in the body. (11) Mechanical stress stemming from activity involving the upper limb has been implicated as a predisposing factor for several conditions affecting the medial clavicle. (16) The susceptibility of the clavicle and sternoclavicular joint to trauma has been well documented and, as in other joints, this may facilitate the onset of degenerative disease. (11) A relatively sparse vascular supply may predispose the clavicular head to degenerative c hanges. (17) The unique development of the clavicular head may predispose younger patients to some lesions at this site. The medial clavicular epiphysis begins to ossify at the age of 18 to 20 years and fuses at the age of 25 years. (17)

The multitude of factors that predispose the medial clavicle to degenerative changes stresses the importance of considering this diagnosis in the differential of a swelling localized to this area. The cases demonstrate that concern for malignancy often results in unnecessary testing and surgical biopsy of patients having clinical and radiographic features consistent with a benign diagnosis. It should be noted that unilateral degenerative changes presenting as asymptomatic enlargement of the medial clavicle have also been observed in two males, but the senior author lacks sufficient follow-up for inclusion in this series. Recognition of benign degenerative changes affecting the medial clavicle, as well as other benign conditions affecting the medial clavicle, may prevent the tendency to misdiagnose and overtreat patients with these conditions, especially those without pain.

Conclusions

We have described our experience with five middle-aged women who presented with asymptomatic chronic swelling of the medial clavicle. In all cases, concern for tumor prompted referral to an orthopedic oncologist. Two cases were biopsied before referral. The patients lacked signs of general illness and inflammation, and none reported a history of overt trauma to the affected area. Imaging demonstrated a variety of changes, probably degenerative in origin. These cases may be related to osteoarthritis of the sternoclavicular joint and condensing osteitis of the clavicle. Prolonged follow-up ranging from 2 to 10 years confirmed the benign nature of the lesion. The lack of pain or other symptoms and the chronicity of the swelling were important features of the cases. Ominous entities including tumor typically cause painful symptoms and change with time. Recognition of a variety of degenerative changes that may manifest as a painless swelling in the area of the medial clavicle may prevent unnecessary testing or su rgical biopsy.

TABLE 1

Differential diagnosis of swelling of the medial clavicle

Etiology                    Characteristic diagnostic features

Osteoarthritis (9-12)       May be asymptomatic in bilateral
                            cases
                            Monarticular cases secondary to
                            trauma invariably report painful
                            symptoms
                            Ostcophytes, sclerosis,
                            cysts, and joint space narrowing
                            are common radiologically

Condensing osteitis         Typically affects middle-aged
 (4-6,13--15,21)            women and causes pain and
                            tenderness
                            Sclerosis and slight
                            enlargement of the clavicular
                            head seen radiologically

Fracture callus (3)         History of trauma in an adult
                            Expansion and ill-defined
                            calcification may be present
                            radiologically

Postoperative               Commonly reported following
 sternoclavicular           homolateral neck dissection
 hypertrophy (16)           Radiographs may show
                            hypertrophy, subluxation, or
                            erosions

Sternocostoclavicular       Typically affects Japanese men
 hyperostosis (17)          Chronic painful symmetrical swelling
                            of the clavicles, upper ribs, and
                            sternum with ossification of
                            intervening soft tissues
                            Associated with pustular lesions
                            of the palms and soles

Friedrich disease (18,19)   Affects children and adolescents
                            Sclerosis of the medial clavicle with
                            associated subehondral radiolucencies
                            and notchlike defects in the articular
                            surface

Pyogenic arthritis (20)     Marked pain and tenderness are
                            usually present
                            Loss of cortical outline and ill-defined
                            bone destruction
                            Fluid or tissue cultures are confirmatory

Chronic osteomyelitis (11)  Bone destruction, periosteal reaction,
                            and inflammation are usually present

Rheumatic disease (11)      Sternoclavicular joint may be affected
                            in rheumatoid arthritis and seronegative
                            arthropathy
                            Pathologic changes are similar to
                            other joints

Dislocation (11)            History of trauma
                            Anterior dislocation is more common

Tumor (2,3,7,8)             Clinical history of pain or discomfort
                            is common
                            Aggressive radiographic features
                            including lytic destruction, extensive
                            sclerosis, and periosteal reaction
                            may be seen
                            Biopsy is diagnostic
                            Primary bone tumors, metastasis, and
                            lymphoma should be considered

Accepted January 22, 2002.

References

(1.) Hamilton-Wood C, Hollingworth P, Dieppe P, Ackroyd C, Watt I. The painful swollen stemo-clavicular joint. Br J Radial 1985;58:941-945.

(2.) Smith J, Yuppa F, Watson RC. Primary tumors and tumor-like lesions of thc clavicle. Skeletal Radial 1988;17:235-246.

(3.) Gerscovich EO, Greenspan A, Szabo RM. Benign clavicular Jesions that may mimic malignancy. Skeletal Radial 199l;20:173-180.

(4.) Kruger GD, Rock MG, Munro TG. Condensing osteitis of the clavicle: A review of the literature and report of three cases. J Bone Joint Surg Am 1987;69:550-557.

(5.) Greenspan A, Gerscovich EO, Szabo RM, Matthews JG II. Condensing osteitis of the clavicle: A rare but frequently misdiagnoscd condition. AJR Am J Roentgenol t991;156:1011-1015.

(6.) Noonan PT, Stanley MD, Sartoris DJ, Resnick D. Condensing osteitis of the clavicle in a man. Skeletal Radial 1998;27:291-293.

(7.) Dahlin DC, Unni KK. Bone Tumors: General Aspects and Data on 8542 Cases. Springfield, IL, Charles C Thomas, 1986, ed 4.

(8.) Barlow IW, Newman RJ. Primary bone tumours of the shoulder: An audit of the Leeds Regional Bone Tumour Registry. J R Call Surg Edinb 1994;39:51-54.

(9.) Silberberg M, Frank EL, Jarrett SR. et al. Aging and osteoarthritis of the human sternoclavicular joint. Am J Clin Pathol 1959;35:851-865.

(10.) Kier R, Wain SL, Apple J, Martinez S. Osteoarthritis of the sternoclavicular joint. Radiographic features and pathologic correlation. Invest Radial 1986;21:227-233.

(11.) Yood RA, Goldenberg DL. Sternoclavicular joint arthritis. Arthritis Rheum 1980;23:232-239.

(12.) Baker ME, Martinez S, Kier R, Wain S. High resolution computed tomography of the cadaveric sternoclavicular joint: Findings in degenerative joint disease. J Comput Tomogr 1988;12:13-18.

(13.) Latifi HR. Gilula LA. Imaging rounds. Bilateral condensing osteitis of the clavicles. Orthop Rev 1992;21:767-774.

(14.) Hsu CY, Frassica F, McFarland EG. Condensing osteitis of the clavicle: Case report and review of the literature. Am J Orthop 1998;27:445-447.

(15.) Junk AG. Noninflammatory sclerosis of the sternal end of the clavicle: A follow-up study and review of the literature. Skeletal Radiol 1994;23:373-378.

(16.) Searle AE, Gluckman P, Sanders R, Breach NM. Sternoclavicular joint swellings: Diagnosis and management. Br J Plast Surg 1991;44:403-405.

(17.) Goossens M, Vanderstraeten C, Claessens H. Sternocostoclavicular hyperostosis: A case report and review of the literature. Clin Orthop 1985;194:164-168.

(18.) Levy M, Goldberg I, Fischel RE, Frisch E, Maor P. Friedrich's disease. Aseptic necrosis of the sternal end of the clavicle. J Bane Joint Surg Br 1981;63:539-541.

(19.) Christensen PB, Christensen I. A case of Friedrich's disease of the clavicle. Acta Orthop Scand 1987;58:585-586.

(20.) Muir SK, Kinsella PL, Trebilcock RG, Blackstone IW. Infectious arthritis of the sternoclavicular joint. Can Med Assac J 1985;132:1289-1290.

(21.) Brower AC, Sweet DE, Keats TE. Condensing osteitis of the clavicle: A new entity. Am J Roentgenol Radium Ther Nucl Med 1974;121:17-21.

RELATED ARTICLE: Case Reports

Patient 1

A healthy 39-year-old professional figure skater presented to her orthopedic surgeon with a 3-year history of "an unsightly bump" on her left chest. She had no pain at rest or with activity. She denied constitutional complaints and any history of overt trauma to the clavicle. She remained an active skater. A computed tomographic (CT) scan revealed sclerosis of the left clavicular head and slight enlargement of the medial third of the clavicle. She was referred to our service due to concern for malignancy.

Examination revealed a nontender, firm, fusiform enlargement that appeared associated with the medial clavicle. The overlying skin was nonerythematous and the sternoclavicular joint was stable. There was no restriction of the range of motion at the shoulder. No laboratory tests were obtained. Further review of her CT scan showed no evidence of periosteal reaction, erosions, or adjacent soft tissue masses. An isolated sclerotic lesion at the medial articular surface of the left clavicle pointed to a diagnosis of condensing osteitis of the clavicle; however, patients with condensing osteitis typically report pain and tenderness. Osteoarthritis at the sternoclavicular joint was also considered but degenerative changes in the adjacent manubrium were lacking. Less likely diagnostic possibilities included pyarthrosis of the sternoclavicular joint, chronic sclerosing osteomyelitis, sternocostoclavicular hyperostosis, and osteoid osteoma. Due to her lack of symptoms and the benign appearance of the lesion on radiogra phic studies, the favored diagnosis was a degenerative condition. The patient was subsequently followed with serial CT scans at declining intervals over a 10-year period. During this period, the swelling partially resolved and the patient remained asymptomatic.

Patient 2

A 71-year-old seamstress with a history of left breast cancer and subsequent left mastectomy presented to a general surgeon due to an 8-month history of a painless swelling of the right anterior chest wall (Fig. 2). Magnetic resonance imaging (MRI) disclosed slight enlargement of the medial clavicle with low signal intensity, consistent with a cystic deformity. Bone scan revealed focal increased uptake in the medial aspect of the right clavicle corresponding to the location of the lesion. Due to the possibility of metastatic breast carcinoma, open biopsy was performed. This revealed dense fibrous connective tissue, fibrocartilage, and focal calcifications, but no evidence of malignancy.

On the basis of her negative biopsy, she was referred to our clinic. Due to her asymptomatic state, she was followed clinically with the tentative diagnosis of a degenerative condition of the medial clavicle. She was instructed to return if she noticed any growth of the mass or began to experience any pain or restriction of arm movement. Over a 5-year period no change in the lesion was observed and the patient remained asymptomatic.

Patient 3

A 52-year-old computer operator presented to our service with a 9-month history of a painless bump on her right chest (Fig. 3). She denied a history of trauma to the affected area.

Examination revealed a firm, nontender swelling that extended laterally approximately 4 centimeters from the sternoclavicular joint and appeared associated with the clavicle. The sternoclavicular joint was stable and the overlying skin was unremarkable. There was no cervical or axillary lymphadenopathy. The patient had a full range of motion at the right shoulder but did first notice slight discomfort at the sternoclavicular joint with extremes of abduction during the examination. Pain was not present at other times.

X-rays demonstrated slight expansion of the medial end of the clavicle and no periosteal reaction or cortical erosions (Fig. 4). CT scan revealed a well-preserved joint space and soft tissue swelling over the medial clavicle. CT reconstruction showed an inferior osteophyte and a small cyst at the inferior articular margin. These radiographic findings were most consistent with a degenerative process. The patient was followed clinically for 2 years with no change in the lesion.

Patient 4

A 46-year-old woman was referred by her family practitioner for consultation of a right shoulder mass. The patient had noted an asymmetry of her chest for several years and believed that the mass had recently increased in size. She did not recall a history of trauma or report any associated symptoms. Examination revealed a firm, nontender mass over the proximal clavicle. The patient had full range of motion at the shoulder. There were no palpable regional lymph nodes and no overlying skin changes.

X-rays and CT scan disclosed marked exophytic sclerotic bone overgrowth of the medial right clavicle and adjacent manubrium (Fig. 5). A serpiginous lucent line at the interface between the exophytic inferior medial clavicle and adjacent exophytic projection from the manubrium suggested a pseudoarthrosis (Fig. 6). The sclerotic appearance of the overgrowth was suggestive of a chronic process. Exuberant posttraumatic degenerative change and exophytic overgrowth was a likely diagnosis. Growth of an osteochondroma at the medial clavicle with reactive exophytic overgrowth from the adjacent manubrium was also considered. Since the patient reported no associated pain or other worrisome symptoms, observation was suggested. CT scan 9 months later revealed no change. She was followed clinically for 5 years without the development of symptoms or any change in the lesion.

Patient 5

A 52-year-old professional watercolor painter presented with a swelling in the lower right neck to the ENT clinic at our hospital. She had no history of trauma and denied pain or other symptoms. She had no prior history of cancer. Fine- Needle aspiration revealed chondroid cells and osteoblasts. CT scan showed degenerative overgrowth about the sternoclavicular joints bilaterally and mild soft tissue swelling over the right sternoclavicular joint (Fig. 7). She was referred to our clinic for further follow-up due to lingering concern for malignancy. Examination revealed a firm, nontender mass at the right sternoclavicular joint. The patient had no pain or restriction of motion at the shoulder. The patient was diagnosed with asymptomatic osteoarthritis of the sternoclavicular joints an was followed without further intervention. The swelling regressed partially over the course of 2 years.

Key Points

* Asymptomatic enlargement of the medial clavicle is seldom malignant.

* Enlargement of the medial clavicle may be associated with sternoclavicular arthritis.

* Painful conditions of the clavicle need full evaluation to rule out malignancy.

From the Department of Orthopaedics, University of North Carolina School of Medicine, Chapel Hill, NC, and the Department of Orthopaedic Surgery, Ohio State University, Columbus, OH.

Reprint requests to Gary D. Bos, MD, Department of Orthopaedic Surgery, Ohio State University, North 1037 Doan Hall, 410 W. 10th Avenue, Columbus, OH 43210. Email: [e-mail]

Copyright [C] 2003 by The Southern Medical Association

0038-4348/03/9603-0310