The cytologic features of NUT midline carcinoma.
BACKGROUND
Nuclear protein in testis (NUT) midline carcinoma (NMC) represents an aggressive, high-grade carcinoma typically involving the upper aerodigestive tract or mediastinum. Although the tumor was originally noted in young persons, we have subsequently identified 5 adult cases. To our knowledge, the cytology of NMC has not been systematically described.


METHODS
We recently published a series of NMCs identified by fluorescent in situ hybridization for characteristic NUT rearrangement. Three of these patients had undergone fine-needle aspiration. Patient age, sex, primary tumor location, and aspiration site were noted. Cases were assessed for the following: cellularity, architecture, cytoplasm, cell size, nuclear contours, nucleoli, chromatin, anisonucleosis/cytosis, mitotic activity, background, and nuclear crush.


RESULTS
The 3 cases occurred in 2 women and 1 man, ages 31-79 years. Primaries involved the sinonasal tract (2) and larynx. Aspirates were of right neck masses (2) and supraclavicular lymph node. Smears were highly cellular and generally noncohesive. Cytoplasm was scant/delicate, although occasional cells with denser cytoplasm were noted in 1 case. Cells were 2-3 times the diameter of a small lymphocyte with irregular nuclear contours, discrete nucleoli, and fine/granular to vesicular chromatin. Anisonucleosis/cytosis was slight to moderate. Mitotic figures were noted in each case. The background contained naked nuclei and karyorrhectic debris; nuclear crush was noted.


CONCLUSIONS
NMCs exhibit cytologic features of a poorly differentiated or undifferentiated carcinoma. Although reports mention squamous differentiation as a histologic feature, it is typically focal, and overt squamous differentiation was not identified in our cases. Given morphologic overlap with other high-grade carcinomas, diagnosis requires a high index of suspicion.
Bellizzi
Andrew M
AM
Department of Pathology, The Ohio State University Medical Center, Columbus, Ohio, USA.
Bruzzi
Cynthia
C
French
Christopher A
CA
Stelow
Edward B
EB
D000328:Adult; D000368:Aged; D018988:Bacterial Translocation; D002277:Carcinoma / Q000235:genetics / Q000473:pathology*; D002884:Chromosomes, Human, Pair 15; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007822:Laryngeal Neoplasms / Q000473:pathology*; D008297:Male; D009296:Nasal Cavity; D009669:Nose Neoplasms / Q000235:genetics / Q000473:pathology*; D009687:Nuclear Proteins / Q000235:genetics*
D009687:Nuclear Proteins