Track: Case Reports

Abstract:

We present a case of a 28-year-old Navy pilot with an eight-year history of a slowly enlarging, firm subcutaneous mass on the left lateral thigh. The lesion was largely asymptomatic but occasionally caused irritation due to friction from clothing and flight gear. He was previously seen by a dermatologist prior to joining the Navy and presumptively diagnosed with an epidermal inclusion cyst, but excision was deferred at that time. The lesion never ruptured or drained any fluid. Exam revealed a 4.5 × 3 cm, freely mobile, extremely firm subcutaneous nodule on the left lateral thigh without overlying punctum. Surgical excision revealed a dense, multilobular, firm white tumor that shelled out easily from the surrounding skin and promptly sank to the bottom of the formalin when transferred to the specimen cup. Histologic examination revealed a biphasic proliferation composed overwhelmingly of large nodules of cartilaginous stroma, with smaller interspersed foci of inconspicuous ducts with epithelial linings and occasional hyalinized pink material filling their lumina. Focal areas of apocrine epithelial morphology were observed in some of these ductal epithelia. These findings were most consistent with a cutaneous mixed tumor, also known as a chondroid syringoma. This case is unique for its atypical location on the lower extremity, the unusually young age of the patient, and the large size of the lesion. We present this case to highlight this uncommon benign entity and to emphasize the pitfall of potential misdiagnosis when the epithelial component constitutes only a small portion of the lesion.