Nut midline carcinoma of the upper aerodigestive tract

Abstract

NUT (nuclear protein in testis) midline carcinoma (NMC) is a rare highly aggressive tumour characterised by chromosomal rearrangements of NUT on 15q14. Initially described in paediatric and adolescent populations, NMC is now known to occur over a wide age range. In adults, a common site of occurrence is the upper aerodigestive tract. We describe the case of a 54-year-old male presenting with 3 months of epistaxis. Examination revealed a mass in the right middle meatus. Biopsy showed a small round blue cell tumour without differentiating histological features. Immuno-histochemically, the tumour was positive for cytokeratins (MNF-116, HMWCK, CK7, CK5), p63, CD99 and CD34. FISH studies for Ewing/PNET and synovial sarcoma translocations were negative. FISH analysis confirmed the presence of the BRD4-NUT rearrangement typical of NMC. The patient underwent cranio-facial resection and post-operative radiotherapy. Follow-up to date has shown no recurrence. NMC is not commonly included in the differential diagnosis of upper aerodigestive tract carcinomas. However, NMC should be considered in any poorly differentiated carcinoma of the upper aerodigestive tract, particularly those co-expressing cytokeratin and CD34. FISH testing for the characteristic translocation confirms the diagnosis. Aggressive therapy has resulted in no evidence of recurrence 18 months after original diagnosis.