NUT midline carcinoma of the larynx: an international series and review of the literature

Aims: NUT midline carcinoma (NMC) is a rare undifferentiated and aggressive carcinoma that locates characteristically to the midline of the head and neck, and mediastinum. NMC is characterized by chromosomal rearrangements of the gene NUT, at 15q14. The BRD4 gene on 19q13 is the most common translocation partner forming a fusion oncogene, BRD4–NUT. By the end of 2014, the International NUT Midline Carcinoma Registry had 48 patients treated for NMC. Laryngeal NMC are exceedingly rare, and we report a case series of seven cases. Methods and results: We searched for cases in files of different hospitals as well as a thorough search of the English language literature. The diagnosis of NMC is made by demonstration of NUT rearrangement either by immunohistochemistry, fluorescence in-situ hybridization (FISH) or reverse transcription–polymerase chain reaction (RT–PCR). We found three previously published cases, and in this series add four cases of our own. Conclusions: NMC consists of monomorphic, often discohesive, cells with an epithelioid appearance and distinct nucleoli. The tumours typically show abrupt squamous differentiation. The mean age of the patients was 34 years, hence significantly lower than that for conventional laryngeal carcinoma. All tumours were located in the supraglottis and five patients died of the disease after 3, 7, 8, 9 and 11 months. Laryngeal NMC may be underdiagnosed, and an increased awareness among pathologists is warranted. NMC has characteristic morphological features, and positive immunostaining with the NUT antibody is diagnostic. Its aggressive behaviour demands a very intense treatment strategy and the need for its recognition is emphasized further by new promising treatment strategies.