Angioleiomyoma of the Foot Presenting as a Ganglion Cyst: A Case of Mistaken Identity.

Angioleiomyoma is an uncommon benign neoplasm originating from the smooth muscle of vascular walls, typically presenting as a painful subcutaneous mass in the lower extremities of middle-aged adults. However, atypical features such as painless growth and unusual anatomical locations can obscure the diagnosis, particularly when limited imaging modalities are used. We present the case of a 62-year-old woman with a 10-month history of right ankle discomfort and a recently enlarging, painless soft-tissue mass over the anterior aspect of the ankle. Radiographic evaluation revealed a subtle soft-tissue prominence adjacent to the first tarsometatarsal joint, without calcifications or osseous involvement. Based on the clinical presentation and radiographs, a ganglion cyst was presumed, and the patient proceeded to surgical excision at her request to relieve symptoms and avoid delays. Intraoperatively, a well-circumscribed, lobulated mass was found superficial to the anterior tibial tendon sheath. Histopathology confirmed a venous-type angioleiomyoma with classic smooth muscle and vascular features, and immunohistochemistry demonstrated strong smooth muscle actin (SMA) positivity. This case illustrates a diagnostic pitfall where reliance on clinical impression and plain radiographs alone may lead to misdiagnosis. It emphasizes the value of contrast-enhanced MRI or ultrasound for preoperative assessment of indeterminate soft-tissue lesions, even when benign pathology is suspected. To our knowledge, this is the first reported case of angioleiomyoma arising adjacent to the anterior tibial tendon insertion at the first tarsometatarsal joint, expanding the known anatomical spectrum of this rare tumor.