Affiliation:
1. Department of Pathology Emory University Hospital Midtown Atlanta GA USA
2. Department of Pathology and Laboratory Medicine Sinai Health System Toronto ON Canada
3. Department of Pathology and Laboratory Medicine Memorial Sloan Kettering Cancer Center New York NY USA
4. Department of Pathology University Health Network Toronto ON Canada
Abstract
Background and aimHead and neck nuclear protein of testis carcinoma (HN‐NUT) is a rare form of carcinoma diagnosed by NUT immunohistochemistry positivity and/or NUTM1 translocation. Although the prototype of HN‐NUT is a primitive undifferentiated round cell tumour (URC) with immunopositivity for squamous markers, it is our observation that it may assume variant histology or immunoprofile.MethodsWe conducted a detailed clinicopathological review of a large retrospective cohort of 30 HN‐NUT, aiming to expand its histological and immunohistochemical spectrum.ResultsThe median age of patients with HN‐NUT was 39 years (range = 17–86). It affected the sinonasal tract (43%), major salivary glands (20%), thyroid (13%), oral cavity (7%), larynx (7%), neck (7%) and nasopharynx (3%). Although most cases of HN‐NUT (63%) contained a component of primitive URC tumour, 53% showed other histological features and 37% lacked a URC component altogether. Variant histological features included basaloid (33%), differentiated squamous/squamoid (37%), clear cell changes (13%), glandular differentiation (7%) and papillary architecture (10%), which could co‐exist. While most HN‐NUT were positive for keratins, p63 and p40, occasional cases (5–9%) were entirely negative. Immunopositivity for neuroendocrine markers and thyroid transcription factor‐1 was observed in 33 and 36% of cases, respectively. The outcome of HN‐NUT was dismal, with a 3‐year disease specific survival of 38%.ConclusionsHN‐NUT can affect individuals across a wide age range and arise from various head and neck sites. It exhibits a diverse spectrum of histological features and may be positive for neuroendocrine markers, potentially leading to underdiagnosis. A low threshold to perform NUT‐specific tests is necessary to accurately diagnose HN‐NUT.