NUT carcinoma in head and neck region: Case report with literature review

Squamous cell carcinoma (SCC) has several variants based on its histopathological features. Nuclear protein in testis (NUT) carcinoma (NC) is a rare and aggressive variant of SCC, previously described exclusively in midline sites. The histopathological features of NC are similar to poorly differentiated carcinoma or undifferentiated carcinoma. Abrupt keratinization in an otherwise undifferentiated carcinoma is an important diagnostic clue. The confirmatory diagnosis is dependent on molecular techniques such as Immunohistochemistry, Fluorescent in situ hybridization technique or RT-PCR to detect mutations in NUT gene. It is most commonly found in middle aged, in lungs and head and neck regions. Since NC features overlap with poorly differentiated and undifferentiated carcinomas, these cases need to be suspected and evaluated for NUT gene mutations thoroughly. Due to their rarity and less known facts, NC cases are required to be reported on large scale.

Here, we report a middle-aged woman with a mass on the forehead diagnosed as NC based on molecular evaluation, with a review of the literature emphasizing the rarity of NUT carcinoma and the importance of careful histopathology as well as immunohistochemistry evaluation.