Diagnostic Dilemma of a Soft Tissue Mass in the Medial Gastrocnemius: A Case Report.

Soft tissue masses in the lower extremities present significant diagnostic challenges due to the broad spectrum of potential etiologies, ranging from benign to malignant tumors. A 69-year-old woman presented to the University of Central Florida-Health Surgical Clinic with an enlarging, firm, ovoid mass in her left gastrocnemius muscle causing increasing mostly emotional and psychological distress. A magnetic resonance imaging (MRI) of the left lower extremity was ordered, and findings suggested a 1.8 × 1.8 × 3.1 cm ovoid mass at the proximal medial head of the gastrocnemius muscle with imaging features most consistent with an intramuscular myxoma. However, the differential diagnosis included other benign and malignant entities, such as schwannoma, ganglion cyst, neurofibroma, lipoma, soft tissue sarcoma, Baker's cyst, bursitis, tenosynovitis, abscesses, and vascular lesions. Surgical excision of the mass revealed a cystic lesion intimately related to the intramuscular portion of the left medial gastrocnemius muscle tendon filled with transparent, gel-like fluid. Histopathological examination confirmed the diagnosis of a ganglion cyst, aligning with the intraoperative findings and providing reassurance of the benign nature of the lesion. The patient's recovery and follow-up were uneventful. This case underscores the complexities involved in diagnosing soft tissue masses in the lower extremities, particularly when initial imaging findings are not straightforward, suggesting multiple potential etiologies.