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

TL;DR

A 69-year-old woman with a soft tissue mass in her calf was diagnosed with a ganglion cyst after surgery, highlighting the difficulty in diagnosing similar leg masses.

Contribution

This case report adds to the understanding of diagnostic challenges in soft tissue masses of the lower extremities.

Findings

MRI findings initially suggested intramuscular myxoma but were inconclusive.

Surgical excision and histopathology confirmed the lesion was a ganglion cyst.

The case highlights the need for careful evaluation to distinguish benign from malignant soft tissue masses.

Abstract

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.

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