Extraskeletal myxoid chondrosarcoma of the finger mimicking a glomus Tumour: A rare case scenario

Abstract

Extraskeletal myxoid chondrosarcoma (EMC) is an extremely uncommon soft tissue neoplasm of chondroblastic origin, predominantly seen in middle-aged and elderly individuals and is more prevalent in males.  It exhibits a predilection for the deep soft tissue of proximal extremities and limb girdles. It is a rare tumour with distinct histology and a characteristic chromosomal translocation, usually t (9;22) (q22;q12.2), fusing EWSR1 to NR4A3. Despite its nomenclature, EMC exhibits no genuine hyaline cartilaginous differentiation and is classified as a tumour of uncertain differentiation in the WHO classification. Histologically, it exhibits myxoid/reticular histology, necessitating immunohistochemistry to aid in its diagnosis. However, molecular methods like fluorescence in-situ hybridization (FISH) are necessary to obtain a definitive diagnosis. In this instance, we detail an uncommon example of an EMC developing in the finger of a middle-aged female that was clinically thought to be a glomus tumour.  Owing to its rare presentation, aggressive nature and tendency to recur, a high index of suspicion by a pathologist is required to diagnose this tricky entity, which can otherwise be readily missed.