Lymphoid neoplasms of the sinonasal tract and their differential diagnoses

Abstract Many types of lymphoid neoplasms have been reported involving the sinonasal region including aggressive and indolent B-cell lymphomas, T/NK cell lymphomas and plasma cell neoplasms. They account for a small percentage of all lymphomas but as a whole is the second most common malignancy in the sinonasal region. Clinically and morphologically, they can mimic non-neoplastic and non-hematolymphoid malignant lesions in this region and must be included in the differential diagnoses when a sinonasal lesion is encountered. This article describes the histopathologic and molecular features of diffuse large B-cell lymphoma and extranodal NK/T cell lymphoma, the two main types of lymphomas found in the sinonasal tract, as well as plasmacytoma and plasmablastic lymphoma, which tend to locate in the head and neck region, and reviews the main differential diagnoses.