NUT carcinoma of the parotid gland: report of two cases, one with a rare ZNF532-NUTM1 fusion

The histological spectrum and immunoprofile of head and neck NUT carcinoma: A multicentre series of 30 cases

BACKGROUND AND AIM

Head 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.

METHODS

We conducted a detailed clinicopathological review of a large retrospective cohort of 30 HN-NUT, aiming to expand its histological and immunohistochemical spectrum.

RESULTS

The 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%.

CONCLUSIONS

HN-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.

Molecularly Defined Thoracic Neoplasms

Molecularly defined neoplasms are increasingly recognized, given the broader application and performance of molecular studies. These studies allow us to better characterize these neoplasms and learn about their pathogenesis. In the thorax, molecularly defined neoplasms include tumors such as NUT carcinoma, SMARCA4-deficient undifferentiated tumor (DUT), primary pulmonary myxoid sarcoma with EWSR1::CREB1 fusion, hyalinizing clear cell carcinoma, and SMARCB1-deficient neoplasms. Overall, these tumors are rare but are now more often recognized given more widely available immunostains such as NUT (NUT carcinoma), BRG1 (SMARCA4-DUT), and INI-1 (SMARCB1-deficient neoplasm). Furthermore, cytogenetic studies for EWSR1 to support a hyalinizing clear cell carcinoma or primary pulmonary myxoid sarcoma are, in general, easily accessible. This enables pathologists to recognize and diagnose these tumors. The diagnosis of these tumors is important for clinical management and treatment. For instance, clinical trials are available for patients with NUT carcinoma, SMARCA4-DUT, and SMACRB1-deficient neoplasms. Herein, our current knowledge of clinical, morphologic, immunophenotypic, and molecular features of NUT carcinomas, SMARCA4-DUT, primary pulmonary myxoid sarcomas, hyalinizing clear cell carcinoma, and SMARCB1-deficient neoplasms will be reviewed.

Clinicopathological molecular characterizations of sinonasal NUT carcinoma: a report of two cases and a literature review

Background

Nuclear protein in testis (NUT) carcinoma (NC) is a rare, aggressive tumor with a typical NUTM1 gene rearrangement.

Methods

Herein, we report a series of 2 cases of sinonasal NC: one in a 16-year-old woman and one in a 37-year-old man. Immunohistochemistry (IHC) staining for NUT (C52B1), fluorescence in situ hybridization (FISH), and next generation sequencing (NGS) sequencing were performed to investigate the morphological and genetic features of sinonasal NC.

Results

The two cases presented similar pathological features and IHC markers, and typical morphological changes, including undifferentiated cells and abrupt keratinization, were observed, with numerous mitotic figures and widespread tumor necrosis. Diffuse expression of NUT, CK, p63, and p40 was noted, while the tumors were negative for synaptophysin, chromogranin A, S-100, EBV-ISH, and PD-L1. Both tumors harbored a NUTM1 rearrangement. Subsequent sequencing revealed a rare BRD3::NUTM1 fusion and a classic BRD4::NUTM1 fusion. In addition, MCL1 copy number gain (2.1), low tumor mutation burden and stable microsatellites, were also confirmed. Case 1 received surgery and chemoradiotherapy but died 13 months after local recurrence and subsequent lung and bone metastasis. Case 2 underwent chemoradiotherapy and unfortunately died from the disease 6 months later. A review of all previously reported cases of sinonasal NCs (n=55) revealed that these tumors occur more frequently in female pediatric patients (n=11, male: female =3:8), whereas this sex difference is not observed in adult patients (n=44, male: female =23:21). The median survival times of pediatric and adult patients were 17 and 13.8 months, respectively.

Conclusion

Sinonasal NC presents typical undifferentiated or poorly differentiated cells, abrupt keratinization features and heterogeneous genotypes, including BRD4::NUTM1 and BRD3::NUTM1 fusions, with low tumor mutation burden and stable microsatellites.

Optical genome mapping identifies a novel pediatric embryonal tumor with a ZNF532::NUTM1 fusion

The molecular characteristics of pediatric brain tumors have not only allowed for tumor subgrouping but have led to the introduction of novel treatment options for patients with specific tumor alterations. Therefore, an accurate histologic and molecular diagnosis is critical for optimized management of all pediatric patients with brain tumors, including central nervous system embryonal tumors. We present a case where optical genome mapping identified a ZNF532::NUTM1 fusion in a patient with a unique tumor best characterized histologically as a central nervous system embryonal tumor with rhabdoid features. Additional analyses including immunohistochemistry for NUT protein, methylation array, whole genome, and RNA-sequencing was done to confirm the presence of the fusion in the tumor. This is the first description of a pediatric patient with a ZNF532::NUTM1 fusion, yet the histology of this tumor is similar to that of adult cancers with ZNF::NUTM1 fusions reported in the literature. Although rare, the distinct pathology and underlying molecular characteristics of the ZNF532::NUTM1 tumor separates this from other embryonal tumors. Therefore, screening for this or similar NUTM1 rearrangements should be considered for all patients with unclassified central nervous system tumors with rhabdoid features to ensure accurate diagnosis. Ultimately, with additional cases, we may be able to better inform therapeutic management for these patients. © 2023 The Pathological Society of Great Britain and Ireland.

Clinical and molecular features of pulmonary NUT carcinoma characterizes diverse responses to immunotherapy, with a pathologic complete response case

PURPOSE

Nuclear protein in testis (NUT) carcinoma is an uncommon malignant cancer characterized by NUTM1 rearrangement. We aimed to investigate the clinicopathological and molecular features and immunotherapy of pulmonary NUT carcinoma.

METHODS

Immunohistochemistry (IHC) for NUT (C52B1) and programmed cell death ligand 1 (PD-L1: 22C3) and fluorescence in situ hybridization (FISH) for NUTM1 break and BRD4-NUTM1 fusion were performed on six pulmonary NUT carcinoma samples.

RESULTS

The 6 pulmonary NUT carcinoma samples were obtained from 5 males and 1 female, with ages ranging from 31 to 73 years (average, 46 years). Five tumors occurred in the lobes, with one in the trachea. Pathologically, all cases showed primitive-appearing round to epithelioid cells growing in nests and sheets. Squamous differentiation and abrupt keratinization were observed. All tumors expressed the NUT protein and p63, and 4 tumors showed focal synaptophysin, but PD-L1 expression was not observed. All cases displayed NUTM1 rearrangement, 5 had BRD4-NUTM1 fusion, and one had an unknown partner. Three patients presented regional lymph node involvement at diagnosis. Five patients underwent intensive radiation and/or chemotherapy. Furthermore, 2 patients (1 and 2) received a combination of PD-L1 inhibitor and chemotherapy. Patient 1 exhibited a poor response and soon showed tumor progression and metastasis; however, patient 2 responded remarkably and achieved pathologic complete response (pCR) without uncontrollable adverse events. The overall survival time was 2.9 months.

CONCLUSIONS

Pulmonary NUT carcinoma exhibits poorly differentiated morphological features with diffuse NUT staining, low PD-L1 expression, and NUTM1 rearrangement. Despite its poor prognosis, it presents a diverse response to immunotherapy. Immune checkpoint inhibitors (ICIs) need to be further explored in NUT carcinoma.

Sinonasal NUT carcinoma: A retrospective case series from a single institution

Purpose

Nuclear protein in testis (NUT) carcinoma is a rare, aggressive tumor defined by the presence of NUT gene rearrangement. The aim of this study was to describe the clinical, radiologic, and biological features of sinonasal NUT carcinoma.

Methods

We retrospectively investigated NUT expression with clinicopathologic features in 145 cases with sinonasal malignancies diagnosed from January 2017 to December 2021 and reviewed the reported cases.

Results

Three (3/145, 2.07%) cases showed strong nuclear expression for NUT immunohistochemical, including one male and two females with ages from 37 to 57 years (mean, 45.33 years). All three cases involved the nasal cavity and sinuses; one of them involved the orbit and intracranial area. Histologically, all subjects showed poorly differentiated, small round cell morphology with distinct nuclei. All patients received surgery and chemoradiotherapy. One patient died of the disease 13 months after diagnosis, and two survived 12 and 15 months, respectively, without evidence of tumor recurrence. 51 cases of sinonasal NUT carcinoma (mean age 40.96 years) have been described to date. Among them, 28 are male, and 23 are female. Most cases expressed p63, AE1/AE3, as well as p40.

Conclusion

NUT carcinoma is a rare and aggressive disease with a poor prognosis. It is crucial to perform NUT rearrangement-related tests for differential diagnosis of poorly differentiated/undifferentiated tumors in the nasal cavity and sinuses.

NUT Carcinoma, an under-recognized malignancy: a clinicopathologic and molecular series of 6 cases showing a subset of patients with better prognosis and a rare ZNF532::NUTM1 fusion

NUT carcinoma (NC) is a rare malignancy with aggressive clinical behavior, defined by rearrangements involving the NUTM1 gene locus. This entity is often under recognized and its diagnosis may be challenging. In this study, we describe a subset of patients that, despite the molecularly proven diagnosis of NC, show improved outcome. In addition, we describe one case with the novel ZNF532::NUTM1 fusion. All cases of NC diagnosed from 2013 to 2022 in our department were retrieved. FISH using dual color bring-together probes and next-generation sequencing assay were performed to characterize the fusions involving NUTM1. Amongst 6 patients identified, 5 were male with a median age of 35.6 years. Four patients had primary tumor in the head and neck region (2 ethmoid sinus, 1 parotid gland, 1 lacrimal gland); 1 in the mediastinum, and another presented with femoral bone tumor. In all cases, the initial diagnoses were not NC. The cases showed different morphological patterns, including monomorphic, rhabdoid and pleomorphic appearance. One case showed pseudopapillary pattern. By immunohistochemistry, all tumors showed squamous differentiation and ≥ 50% of neoplastic cells with nuclear positivity for NUT antibody. One case expressed WT1 (C-terminus) and other showed chromogranin positivity. Genetic study revealed a BRD4::NUTM1 fusion in all head and neck cases, BRD3::NUTM1 in mediastinum case, and ZNF532::NUTM1 fusion in the femur bone case. They were treated with surgical resection plus chemo and radiotherapy. The median overall survival was 23.11 months (1.6-83.3 mo) and the median disease free survival was 14.86 months (0-54.4 mo). The patients with longer overall survival were one with a lacrimal gland primary (83.3 months) and other with a parotid lesion (31.9 months). Both patients were primarily treated with complete surgical resection. Anatomic location may be directly related to the overall survival in NC cases. Resectability of the lesion is also an important factor related to survival. Pathologists should include NC in the differential diagnosis of any poorly differentiated and undifferentiated monomorphic malignancy, regardless of its anatomic location.