Unmasking the Rare: Diagnostic Challenges in Sellar Chondromyxoid Fibroma and Cervical Spine Chondrosarcoma—Two Unusual Head and Neck Cases

ABSTRACT: Chondrogenic tumors of the head and neck are exceptionally rare and pose significant diagnostic challenges due to their clinical and radiologic resemblance to more common sellar and spinal lesions. We report two unusual cases: a chondromyxoid fibroma involving the sellar region in a 32-year-old man presenting with diplopia and headache, and a cervical spine chondrosarcoma in a 42-year-old man presenting with progressive quadriparesis. Magnetic resonance imaging in the first case revealed a well-circumscribed extra-axial sellar mass that was completely excised, with histopathology demonstrating lobulated stellate-to-spindle cells in a chondromyxoid stroma and immunonegativity for EMA, GFAP, and Brachyury, confirming chondromyxoid fibroma. The second case showed an expansile C2 vertebral lesion with infiltrative chondrogenic histology, binucleated chondrocytes, and strong D2-40 positivity with SATB2 and Brachyury negativity, consistent with Grade II chondrosarcoma. While the chondromyxoid fibroma patient remains disease-free at 24-month follow-up, the chondrosarcoma patient experienced rapid progression and succumbed within eight months postoperatively. These cases highlight the critical role of integrating radiologic features, histomorphology, and targeted immunohistochemistry in distinguishing benign from malignant chondroid tumors at anatomically complex sites, enabling appropriate management and prognostication.