Cytological features of NUT midline carcinoma arising in sino‐nasal tract and parotid gland: Report of two new cases and review of the literature

Abstract

Nuclear Protein in Testis (NUT) Midline Carcinoma (NMC) represents a recently described, uncommon, high-grade and extremely lethal malignancy mainly occurring in children and young adults. Such tumors are genetically characterized by chromosomal rearrangements of the NUT gene. Cytological description of NUT carcinoma is limited and only seven cases were reported up to date. We show here another two cases studied cytologically with molecular and immunohistochemical confirmation. In both cases smears were hypercellular and composed of isolated or clustered small to medium-sized in size with roundish and oval shape cells. Nuclei were either regular or roundish containing dusty chromatin and prominent nucleoli. Mitotic figures were prominent. Cytoplasm was scant, strongly basophilic. Cell debris, necrosis, and apoptosis were also prominent. One of the cases was studied by FISH and the second case was studied by RT-PCR and BRD4-NUT translocation was found in both cases. Moreover, the clinical evolution was aggressive in both cases with rapid fatal clinical outcome. NUT carcinomas are an underdiagnosed entity which should be taken into consideration when poorly differentiated carcinomas was diagnosed in children or young adults. Cytology material may be successfully used for morphological and molecular diagnosis. Diagn. Cytopathol. 2016;44:753-756. © 2016 Wiley Periodicals, Inc.

Nuclear protein in testis (NUT) carcinoma diagnosed using only FNA material in the absence of a histological sample

“…All case reports and case series describe smears as being highly cellular with a predominant dissociated cell component . The cells are observed as being primitive appearing and having small to intermediate sized, oval to round nuclei with a single small distinct nucleolus similar to the present case .…”

“…Mitotic count is described as being variable. Most case reports describe the cytoplasm of NUT carcinoma cells as scant and dense, although a few case reports have described cells with fine vacuolations . Santis et al describe giant and multinucleated cells, similar to those seen in our patient; however, many previous reports have not made this observation .…”

NUT carcinoma in children and adults: A multicenter retrospective study

“…The main differential diagnosis is Ewing's sarcoma/primary neuroectodermal tumor . NUT carcinoma can also be confused with rhabdomyosarcoma, biphasic forms of synovial sarcoma, undifferentiated carcinomas of the nasopharynx, carcinoma of the salivary glands, small cell desmoplastic tumors, or rhabdoid tumors. Case NMC 7 presented an unusual immunological profile with negative staining for several anticytokeratin antibodies with a particularly broad spectrum (KL1, AE1‐AE3, CK7, CK20, CK8‐18) and the presence of myeloid markers (CD45, CD68, myeloperoxidase, TdT, CD15).…”

NUT midline carcinoma as a primary lung tumor: a case report

“…Both of them were considered originating from thymus (6,7). Since then, cases originating from different organ sites have been reported and explored in depth (1,2,(8)(9)(10)(11). This unique tumor characteristic of a relatively consistent chromosomal rearrangement is not defined by the site of origin but rather defined genetically.…”