ERG expression in chondrogenic bone and soft tissue tumours: importance of antibody clone. Comment on Shon et al (2015)

A Rare Case of Myxochondroid Metaplasia of the Plantar Foot With Review of Histopathological Mimics

ABSTRACT

Chondromyxoid metaplasia can rarely lead to the formation of a distinctive tumor-like proliferation in the plantar foot. This is thought to represent a reactive or reparative process, possibly due to chronic trauma. For the unwary dermatopathologist, this could represent a diagnostic challenge. Herein, we review the clinical, histopathological, and molecular presentation of an athletic 17-year-old boy with a soft tissue mass arising in the right plantar foot. Microscopic examination showed a relatively circumscribed proliferation of spindle cells with abundant chondromyxoid stroma, hyalinization, and diffuse ERG reactivity. We also review characteristics of this entity that help differentiate it from clinical and histopathologic mimics and postulate possible links with soft tissue chondromas and immature chondroid choristoma.