Sinonasal lymphoma is a rare malignancy. Sinonasal lymphomas are mainly non-Hodgkin’s lymphomas as Hodgkin’s lymphomas are rarely found outside lymph nodes. Most sinonasal non-Hodgkin’s lymphomas in western countries originate from B cells, whereas in Asia non-Hodgkin’s lymphomas are mainly of T-cell or NK-cell origin. In Taiwan, it is uncommon to find sinonasal B-cell lymphoma. The diagnosis of sinonasal lymphoma is often missed as its early symptoms are non-specific. Deep biopsies are necessary for adequate tissue collection. However, sinonasal lymphomas often cause considerable destruction of bony structures on presentation. The utilization of computer-assisted navigation system (CANS) ensures safety during surgery. A 79-year old female came to our hospital due to right nasal obstruction and intermittent right epistaxis for several months. Computed tomography scan demonstrated an infiltrativ tumor sized 3.1 × 2.2 × 3.4 cm that originated from the right ethmoid sinus with bony destruction of the right medial orbital wall, right frontal sinus, and right middle turbinate. Transnasal endoscopic sinus surgery was performed for tumor deep biopsy and volume reduction with the aid of CANS. Histopathological and immunophenotypic analysis showed diffuse large B-cell lymphoma (DLBCL), with a diagnosis of stage IIE disease according to the Ann Arbor staging system. The patient received subsequent cycles of rituximab combined with systemic chemotherapy and responded well to the treatment. (J Taiwan Otolaryngol Head Neck Surg 2022; 57:233-238)
