Extraskeletal Myxoid Chondrosarcoma Presenting as a Plantar Fibroma: Case Report and Review of the Literature

Abstract

Background: Extraskeletal myxoid chondrosarcoma is a rare tumor with an indolent course, high propensity for local recurrence, metastases, and propensity for the proximal extremities of middle-aged males.

Case report: We present the case of a 44-year-old man with an extraskeletal myxoid chondrosarcoma in the plantar fascia of the medial arch initially thought to be a plantar fibroma. Magnetic resonance imaging of the lesion demonstrated a lobulated subcutaneous mass plantar to the tarsal bones and inseparable from the fascia. Microscopic examination revealed a lobulated lesion composed of cords and nests of round to spindled malignant cells in a blue-gray myxoid matrix surrounded by fibrous septae. The malignant cells displayed variable positivity for S-100.

Conclusion: Plantar extraskeletal myxoid chondrosarcoma is a rare occurrence. It should always be considered in the differential diagnosis of masses arising in the plantar fascia of the foot.

Keywords: Extraskeletal myxoid chondrosarcoma; plantar fibroma.