Extra-Axial Soft Tissue Chordoma of Hand: A Rare Case Report.

Introduction: Conventional chordoma is a malignant osseous neoplasm that usually arises from the axial skeleton. It recapitulates a phenotype of embryonic notochord, usually occurring in the 5th-7th decades of life. Very rarely, chordomas can arise in the extra-axial skeleton, more so in the extra-axial soft tissues. We present one such case of Extra-axial soft tissue chordoma in the dorsum of the hand in an adult patient, with a short review of the literature.

Case report: A 48-year-old male patient presented with a longstanding swelling on the dorsum of the left hand, persisting for 5 years. Clinico-radiological assessment suggested differential diagnoses of a ganglion cyst or a chondroid lesion. A fine needle aspiration was performed, which was documented as a giant cell-rich soft tissue neoplasm. Subsequent excision biopsy showed histopathological features characterized by numerous multivacuolated, bubbly cytoplasmic physaliferous cells within a myxohyaline matrix, indicative of a neoplastic process. Immunohistochemistry revealed positivity for brachyury, which confirmed the diagnosis of an Extra-axial soft tissue chordoma.

Conclusion: Extra-axial soft tissue chordomas are extremely rare malignant osseous neoplasms that can mimic a variety of other lesions, need a strong clinical suspicion, and keen morphological cum immunohistochemical examination for diagnosis. Given their similar imaging characteristics and overlapping histological features, making an accurate diagnosis is crucial, as treatment plans vary significantly.