Extra-Axial Chordoma of the Hand.

Chordomas are low-grade malignant tumors that are locally aggressive and have the potential to metastasize. They most often occur in the sacrococcygeal and spheno-occipital portions of the vertebral column. Morphologically similar tumors have been found outside the axial skeleton and are referred to as extra-axial chordomas. Several case reports have described the radiologic, microscopic, and immunologic profiles of these tumors and their similarities to axial chordomas. The authors report a 24-year-old man who presented with a mass in his left hand and underwent surgical excision. Specimens stained positive for pancytokeratin, S100, and brachyury. Brachyury is a protein that is present during embryogenesis and is expressed by chordomas. This is the first report of an extra-axial chordoma within the interosseous muscle compartment of the hand in a young patient.