Malignant fibrous histiocytoma of maxillary sinus- a diagnostic challenge.

Malignant fibrous histiocytoma (MFH) is a malignant mesenchymal tumor uncommonly seen in head and neck region and even rarer in maxillary sinus with less than thirty cases reported in literature. Microscopic diagnosis at this rare site may be challenging because of the spectrum of features, which frequently overlap with other benign and malignant tumors. We herein report a case of malignant fibrous histiocytoma of the maxillary sinus in a 40-year-old man who presented with epistaxis. The initial biopsy appeared benign whereas histopathology of wide surgical excision was consistent with MFH. In view of the deep location, the diagnosis may be missed on a small biopsy, which can appear deceptive leading to diagnostic errors. This case report highlights the histopathological difficulties and pitfalls of this tumor at this rare site.