Usefulness of Nuclear Protein in Testis (NUT) Immunohistochemistry in the Cytodiagnosis of NUT Midline Carcinoma: A Brief Case Report.

Nuclear protein in testis (NUT) midline carcinomas are uncommon, recently described, fatal neoplasm that are characterized by rearrangement of the NUT gene on 15q14.1 Since the first case of NUT midline carcinoma was reported as an undifferentiated carcinoma with a t(15;19) translocation in 1991,2 more than 50 cases have been reported.3 Because of the unique chromosomal translocation and predilection for occurrence in midline structures, they have been termed NUT midline carcinomas. However, tumors outside the midline have been reported, including the salivary gland, bladder, and other sites.1,3,4,5 We encountered a case of NUT midline carcinoma confirmed by NUT specific immunohistochemistry (IHC) using cytologic and histologic specimens. Herein, we present the first case report on immunocytologic features of NUT midline carcinoma arising in the parotid gland.