Sphenoid sinus chondromyxoid fibroma mimicking a mucocele.

We report the case of a 44-year-old man who presented with a chondromyxoid fibroma (CMF) of the sphenoid sinus, which filled the sinus and clinically and radiologically resembled a mucocele. Chondromyxoid fibromas are the least common cartilaginous neoplasms of bone, typically occurring in the metaphysis of long bones. They have occasionally been described in the facial bones, usually the mandible and maxilla, and rarely involve the paranasal sinuses. Chondromyxoid fibroma displays a relatively unique histological appearance, with characteristic lobulation, with spindle to stellate cells embedded in a myxoid or chondroid matrix. The periphery of the lobules tends to be more cellular than the center. Despite having been described nearly 60 years ago, the histogenesis of CMF remains controversial. Although CMFs are generally regarded as benign neoplasms, they may show an infiltrative pattern and may recur, particularly when they are in locations where complete surgical excision may be difficult or impossible.