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


METHODS
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.


CONCLUSIONS
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.
Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, U.S.A.
Megan G
MG
Lockyer
Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, U.S.A. dgrosen@bcm.edu.
Daniel G
DG
Rosen
D000328:Adult; D002813:Chondrosarcoma / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005350:Fibroma / Q000175:diagnosis*; D005534:Foot Diseases / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D018204:Neoplasms, Connective and Soft Tissue / Q000175:diagnosis*; D011379:Prognosis
Extraskeletal myxoid chondrosarcoma; plantar fibroma