NUT Midline Carcinoma: A Series of Five Cases, Including One with Unusual Clinical Course

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.

Sinonasal NUT carcinoma: A consecutive case series and systematic review

BACKGROUND

Sinonasal NUT carcinoma is an extremely rare, lethal malignancy with limited literature.

METHODS

A case series was conduction of all patients with sinonasal NUT carcinoma at a single institution between 2010 and 2022. Survival and associated were evaluated. A systematic review of the literature was performed.

RESULTS

In 12 patients, followed for a median of 1.5 years, the median overall survival (OS) and disease-specific survival (DSS) were both 14.6 months. Patients with maxillary sinus tumors were 91% more likely to survive (hazard ratio [HR]: 0.094, 95% confidence interval [CI]: 0.011-0.78, p = 0.011). Patients with higher-stage disease stage had worse OS (stage IVb-c vs. III-IVa, p = 0.05). All three patients who were alive with no evidence of disease received induction chemotherapy.

CONCLUSION

For patients with sinonasal NUT carcinoma, the median survival was 15 months but better with lower-stage and maxillary tumors. Induction chemotherapy may be beneficial.

NUT carcinoma of the mandible in a child: case report and systematic review

Nuclear protein of the testis (NUT) carcinoma is a rare, undifferentiated carcinoma that is characterized by NUTM1 gene rearrangements. Patients with NUT carcinoma have an overall survival of approximately 5% at 5 years despite a multimodal treatment approach. This report illustrates the management of mandibular NUT carcinoma in a pediatric patient, complemented by a systematic review of head and neck NUT carcinoma. A 5-year-old female presented with an enlarging jaw mass that was diagnosed as BRD4-NUTM1 carcinoma and was treated with hemimandibulectomy and chemoradiation. She remains disease-free 21 months after completion of therapy. A total of 63 patient cases reported in 34 articles were identified in the review. Only 26.9% (14/52) of tumors were correctly diagnosed initially as NUT carcinoma, whereas 73.1% (38/52) were incorrectly diagnosed as another malignancy; the initial diagnosis was not reported for 11 patients. The mandibular tumor subtype was among the rarest reported (n = 1; 1.6%). Combination therapy, including surgery and chemoradiation, was the most common treatment (55.2%). The patient case presented here is a novel case of pediatric mandibular NUT carcinoma. Due to the poor overall survival of patients with NUT carcinoma, aggressive upfront resection with 2-cm margins followed by adjuvant chemoradiation is advocated.

Clinicopathological features and prognostic outcomes of molecularly defined entities in the new edition of the WHO classification of sinonasal carcinoma

Introduction

We investigated the clinicopathological features and prognoses of the new molecularly defined entities in latest edition of the World Health Organization (WHO) classification of sinonasal carcinoma (SNC).

Methods

Integrated data were combined into an individual patient data (IPD) meta-analysis.

Results

We included 61 studies with 278 SNCs including 25 IDH2-mutant, 41 NUT carcinoma, 187 SWI/SNF loss, and 25 triple negative SNCs (without IDH2 mutation, NUTM1 rearrangement, and SWI/SNF inactivation) for analyses. Compared to other molecular groups, NUT carcinoma was associated with a younger age at presentation and an inferior disease-specific survival. Among SNCs with SWI/SNF inactivation, SMARCB1-deficient tumors presented later in life and were associated with a higher rate of radiotherapy administration. SMARCA4-deficiency was mostly found in teratocarcinosarcoma while SMARCB1-deficient tumors were associated with undifferentiated carcinoma and non-keratinizing squamous cell carcinoma.

Conclusion

Our study facilitates our current understanding of this developing molecular-defined spectrum of tumors and their prognoses.

The whole treatment process and thinking of a patient with NUT carcinoma of the parotid gland: a case report

Background

Primary nuclear protein in testis (NUT) carcinoma is a rare malignant tumor originating from the salivary glands that usually occurs in midline structures, such as the head and neck, and has been identified in young patients. Progression of NUT carcinoma is rapid, and there is a high degree of malignant invasion. The median survival time of NUT carcinoma patients is 6 to 9 months, and 80% of the patients die within 1 year after diagnosis.

Case description

This case report summarizes the treatment of a 36-year-old male patient with NUT carcinoma of the right parotid gland. The overall survival of the patient was 2 years. We also discuss the applications and outcomes of immune checkpoint inhibitor and targeted therapy combination regimens in the treatment of NUT carcinoma.

Conclusion

We suggest that targeted therapy combined with immunotherapy which has long-term clinical benefits and targeted therapy which has high clinical response rate(immunotherapy + dual-targeting three-drug regimens) is an ideal choice for the treatment of patients with rare and/or refractory tumors and will not compromise patient safety.

Clinical trial registration

identifier ChiCTR1900026300.

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.

IDH1/2 Mutations in Sinonasal Undifferentiated Carcinomas: Previously Undescribed IDH2 R172K and R140x Variants

Sinonasal undifferentiated carcinoma (SNUC) is a rare, poorly defined sinonasal epithelial neoplasm from which several genetically defined entities are emerging.IDH1/2mutations were recently identified in a subset of SNUC. However, the ideal method for the detection of these mutations remains to be established. Cases diagnosed as SNUC between 2010 and 2020 were retrieved. Immunohistochemistry was performed using IDH1/2 mutant-specific antibody MsMab-1. Quantitative real-time polymerase chain reaction (qPCR) was performed on genomic DNA extracted from formalin-fixed paraffin-embedded tissue using 2 kits to detectIDH1/2mutations. Sanger sequencing was performed in a subset of cases. Thirty-eight cases of SNUC were identified, 18 of which showedIDH1/2mutations by qPCR (47.4%).IDH2R172K and R140x were most frequent, each seen in 6 cases (33.3%). Sanger sequencing identifiedIDH1/2mutations in 4 out of 21 cases (19%) and did not detect mutations identified by qPCR in 7 cases. On immunohistochemistry, strong IDH positivity was present in 2 cases (5.3%), 1 of which hadIDH2mutation, while no mutation was detected in the other. Our results demonstratingIDH2R172K andIDH2R140x variants are a novel finding in SNUC. Immunohistochemistry and Sanger sequencing have low sensitivity for detection ofIDH1/2mutations, and qPCR-based assays may be utilized, particularly in resource-limited settings where access to sophisticated sequencing techniques are difficult.

SMARCA4/BRG1-Deficient Sinonasal Carcinoma: Morphologic Spectrum of an Evolving Entity

CONTEXT.—

Molecular analysis of poorly differentiated/undifferentiated sinonasal neoplasms has resulted in identification of a growing number of genetically defined tumors. SMARCA4-deficient sinonasal carcinoma is one such recently described entity that emerged from within sinonasal undifferentiated carcinoma (SNUC), neuroendocrine carcinoma (NEC), and teratocarcinosarcoma (TCS).

OBJECTIVE.—

To identify SMARCA4-deficient sinonasal carcinomas from a large institutional cohort of poorly differentiated/undifferentiated carcinomas and evaluate their clinicopathologic features.

DESIGN.—

SMARCA4/BRG1 immunohistochemistry was performed on all tumors diagnosed as SNUC, poorly differentiated carcinoma, NEC, and TCS during a 12-year period. SMARCA2/BRM and INSM1 immunostaining was performed in SMARCA4-deficient cases.

RESULTS.—

Twelve SMARCA4-deficient sinonasal carcinomas were identified among 299 cases. Morphologically, 5 cases were large cell NEC, 2 cases were small cell NEC, and 5 were TCS. SMARCA4 loss was diffuse and complete in 10 cases, while 2 cases showed focal retention. Most cases showed diffuse cytokeratin staining accompanied by weak, usually focal staining for chromogranin and synaptophysin. INSM-1 showed negativity in most cases. All cases showed retained SMARCA2 expression. IDH1/2 mutation was absent in all cases analyzed. Four of 7 patients died of disease, and aggressive multimodality treatment had better outcome.

CONCLUSIONS.—

SMARCA4-deficient sinonasal carcinomas are morphologically akin to sinonasal poorly differentiated NECs and TCS, display cytokeratin positivity and only focal staining for neuroendocrine markers, and have aggressive biological behavior. Inclusion of SMARCA4 in the immunohistochemical panel for diagnostic workup of all sinonasal NEC and TCS phenotypes will facilitate their early recognition. Comprehensive germline and somatic mutational analyses of these tumors are necessary for further insights into their molecular pathogenesis.

NUTM1-Rearranged Neoplasms-A Heterogeneous Group of Primitive Tumors with Expanding Spectrum of Histology and Molecular Alterations-An Updated Review

Nuclear protein of testis (NUT), a protein product of the NUTM1 gene (located on the long arm of chromosome 15) with highly restricted physiologic expression in post-meiotic spermatids, is the oncogenic driver of a group of emerging neoplasms when fused with genes involved in transcription regulation. Although initially identified in a group of lethal midline carcinomas in which NUT forms fusion proteins with bromodomain proteins, NUTM1-rearrangement has since been identified in tumors at non-midline locations, with non-bromodomain partners and with varied morphology. The histologic features of these tumors have also expanded to include sarcoma, skin adnexal tumors, and hematologic malignancies that harbor various fusion partners and are associated with markedly different clinical courses varying from benign to malignant. Most of these tumors have nondescript primitive morphology and therefore should be routinely considered in any undifferentiated neoplasm. The diagnosis is facilitated by the immunohistochemical use of the monoclonal C52 antibody, fluorescence in situ hybridization (FISH), and, recently, RNA-sequencing. The pathogenesis is believed to be altered expression of oncogenes or tumor suppressor genes by NUT-mediated genome-wide histone modification. NUTM1-rearranged neoplasms respond poorly to classical chemotherapy and radiation therapy. Targeted therapies such as bromodomain and extraterminal domain inhibitor (BETi) therapy are being developed. This current review provides an update on NUTM1-rearranged neoplasms, focusing on the correlation between basic sciences and clinical aspects.

Diagnosis of NUT Carcinoma Despite False-Negative Next-Generation Sequencing Results: A Case Report and Literature Review

Nuclear protein in testis (NUT) carcinoma (NC) is a poorly differentiated malignant tumor with a poor prognosis, which is caused by the NUTM1 gene rearrangement. Positive staining of NUT using immunohistochemistry (IHC) or gene rearrangement of NUTM1 revealed by genetic analysis, such as fluorescence in situ hybridization (FISH) or next-generation sequencing (NGS), are important strategies used for accurate diagnosis. In the current study, we present a case of NC in an 18-year-old man who had a chief complaint of nasal congestion, nasal bleeding, and anosmia. Magnetic resonance imaging revealed a mass in the nasal cavity and nasal septum. The initial pathological diagnosis was basaloid squamous cell carcinoma. Based on the tumor location and abrupt keratinization, further genetic tests were performed, and NC was diagnosed using FISH, which was further verified by IHC. However, neither DNA-based NGS nor RNA-based NGS revealed the NUTM1 gene rearrangement. Using this case as a basis, we have reviewed the related literature, compared the common diagnostic methods of NC, and discussed the advantages and limitations of current tools employed for molecular analysis of the gene fusion.

Update on genetically defined lung neoplasms: NUT carcinoma and thoracic SMARCA4-deficient undifferentiated tumors

NUT carcinoma, also known as NUT midline carcinoma, is an aggressive malignancy mainly affecting the midline structures of younger patients and almost invariably leading to death within a few months of the diagnosis. Morphologically, NUT carcinoma consists of sheets of monomorphous small or medium size cells with scant cytoplasm, commonly featuring areas of abrupt squamous differentiation with keratinization. Immunohistochemistry for NUT protein is sensitive and specific, typically showing a speckled nuclear reactivity, assisting in diagnosis. The molecular background of NUT carcinoma includes the reciprocal translocation t(15;19) leading to expression of the BRD4-NUT fusion transcript with oncogenic properties. Other less common genes may occasionally be fused with NUT not only in NUT carcinoma but also in other soft tissue tumors, highlighting the fact that NUT-rearranged tumors may represent a larger and more diverse family of neoplasms. Thoracic SMARCA4-deficient undifferentiated tumors are aggressive malignancies diagnosed more often in young male smokers, which often lead to death within a few months. SMARCA4-deficient tumors show undifferentiated morphology with occasional hepatoid and rhabdoid features. Immunohistochemically, the hallmark of diagnosis is loss of expression of SMARCA4 (BRG1). Concurrent loss of SMARCA2 expression, as well as expression of one or more stem cell markers SOX2, CD34, or SALL4 is common. Truncating mutations in SMARCA4, a catalytic subunit of the mammalian BAF (SWI/SNF) complex, are the dominant oncogenic molecular event underlying the pathogenesis of these tumors. SMARCA4 deficiency can also be seen as a passenger somatic event in multiple solid neoplasms manifesting as focal dedifferentiation and rhabdoid morphology.

Cytomorphology of primary pulmonary NUT carcinoma in different cytology preparations

BACKGROUND

NUT carcinoma (NC) is an aggressive neoplasm that often presents with alarge tumor burden and metastases; cytology is frequently one of the primary diagnostic modalities. Primary pulmonary NCs are very rare and cytology descriptions are limited. The current study was performed to analyze the cytomorphological features of primary pulmonary NCs in different cytology samples and preparations.

METHODS

A total of 15 cytology specimens from 10 patients with primary pulmonary NCs diagnosed primarily on histology were retrieved and reviewed.

RESULTS

Fifteen cytology samples, including aspirates from primary (5 samples) and metastatic (5 samples) sites, sputum (1 sample), and effusions (4 samples), that were prepared as direct smears, centrifuged smears, and cell blocks were reviewed. Aspirate smears from all cases were cellular and demonstrated fragments and cohesive clusters of primitive tumor cells with scant cytoplasm, ovoid nuclei with coarse granular chromatin, and consistently conspicuous single nucleoli in a frequently neutrophil-rich necrotic background with dispersed bare tumor nuclei. In fluid cytology, tight, 3-dimensional tumor clusters and singly lying tumor cells were observed. Squamous differentiation in the form of sheets and singly lying polygonal tumor cells with abundant dense cytoplasm was noted focally in rare cases. The diagnoses during original sign-outs were poorly differentiated carcinoma, poorly differentiated squamous cell carcinoma, and malignant small round cell tumor. NUT-1 (NUT family member 1 protein) immunocytochemistry performed on cell blocks demonstrated characteristic speckled nuclear staining in tumor cells.

CONCLUSIONS

Pulmonary NC presents as a poorly differentiated carcinoma with focal to absent squamous differentiation on cytology. Cellular fragments of primitive tumor cells with conspicuous nucleoli should raise suspicion of NUT carcinoma and prompt ancillary testing.

Prevalence of NUT carcinoma in head and neck: Analysis of 362 cases with literature review

BACKGROUND

Nuclear protein in testis (NUT) carcinoma is a poorly differentiated carcinoma defined by the presence of NUT gene rearrangement. In the head and neck, the true prevalence of NUT carcinoma is unknown.

METHODS

We retrospectively investigated NUT expression with clinicopathologic features in 362 patients of poorly differentiated or undifferentiated carcinomas in the head and neck, and reviewed the literature reports.

RESULTS

Four (4/362, 1.1%) cases showed strong nuclear expression for NUT-specific monoclonal antibody, and all these tumors were in the sinonasal tract (4/40, 10%). The clinical outcome and histology were diverse unlike previously described. Although previous studies reported different frequency results according to study subjects, frequencies in sinonasal tract are relatively constant (10/80, 12.5%).

CONCLUSIONS

This is the largest study on the prevalence of NUT carcinoma in head and neck areas. It is important to include in the differential diagnosis of poorly differentiated carcinoma, particularly in the sinonasal tract.

An Overview of Molecular Mechanism, Clinicopathological Factors, and Treatment in NUT Carcinoma

NUT carcinoma (NC) is a rare and poorly differentiated tumor, with highly aggressive and fatal neoplasm. NC is characterized by chromosomal rearrangement involving NUTM1 gene, but lack of specific clinical and histomorphological features. It is more common in midline anatomic sites, such as head and neck, mediastinum, and other midline organs. NC may occur at any age, but mainly in children and young adults. In addition, male and female are equally affected. Most clinicians lack a clear understanding of the disease, and NC diagnostic reagents are still not widely used; therefore, misdiagnosis often occurs in clinic. Due to the highly aggressive nature of the disease and the insensitivity to nonspecific chemotherapy or radiotherapy, many patients have died before the confirmation of NC. In fact, the true incidence of NC is much higher than the current statistics. In recent years, targeted therapy for NC has also made some progress. This article aims to summarize the molecular mechanisms, clinicopathological characteristics, and treatment of NC.

Updated WHO nomenclature of head and neck lesions and associated imaging findings

This article reviews the imaging features of head and neck lesions with updated 2017 World Health Organization (WHO) nomenclature. The major WHO changes include refined terminology of existing entities, descriptions of new tumor types, elimination of defunct categories, and updated biological characterization of various tumor types. In particular, the updates pertaining to the following conditions will be reviewed: tumors of the oral cavity and oropharynx, including HPV-positive or HPV-negative squamous cell carcinoma, small cell carcinoma; tumors of the hypopharynx, larynx, trachea, and parapharyngeal space, including nomenclature revisions for laryngeal neuroendocrine tumors; tumors of the nasal cavity and paranasal sinuses including newly added entities such as NUT carcinoma and biphenotypic sinonasal sarcoma; odontogenic and maxillofacial bone tumors, including the reversal of terminology for certain cystic lesions; tumors of the salivary glands, including updated terminology related to high-grade transformation and polymorphous adenocarcinomas tumors; temporal bone lesions including modifications of the nomenclature and classification criteria; tumor-like lesions of the neck and lymph nodes, with a discussion encompassing developmental cysts, metastases of unknown primary, and heterotopia-associated neoplasia; and mucosal melanoma. Familiarity with the proper WHO terminology for conditions that might be mentioned in differential diagnoses and a general understanding of the behavior of head and neck lesions can help optimize imaging assessment and reporting.

NUT Carcinoma of the Salivary Glands: Clinicopathologic and Molecular Analysis of 3 Cases and a Survey of NUT Expression in Salivary Gland Carcinomas

NUT carcinoma (NC) represents a rare subset of highly aggressive poorly differentiated carcinomas characterized by rearrangement of the NUT (aka NUTM1, nuclear protein in testis) gene, most commonly fused to BRD4. Originally described as a mediastinal/thymic malignancy, NC has been reported at a variety of anatomic regions including the upper and lower aerodigestive tract. To date, only 7 NC cases of probable salivary gland origin have been reported. We herein describe 3 new cases (all affecting the parotid gland) in 2 women (39- and 55-y old) and 1 man (35-y old). Histologic examination showed poorly differentiated neoplasms composed of poorly cohesive small-sized to medium-sized cells with variable squamoid cell component that was focal and abrupt. Immunohistochemistry showed uniform expression of p63 and distinctive punctate expression of the NUT antigen in the tumor cell nuclei. Review of the reported salivary gland NC cases (total, 10) showed a male:female ratio of 1.5:1 and an age range of 12 to 55 years (median, 29 y). Site of the primary tumor was the parotid (7), sublingual (2), and submandibular (1) glands. All presented as rapidly growing masses treated by surgery followed by adjuvant radiotherapy/chemotherapy. Initial nodal status was positive in 8/10. At last follow-up (1 to 24 mo; median, 5 mo), 7/10 patients died of disease at a median of 5.5 months (1 to 24 mo) and only 2 were disease free at 7 and 14 months. Of 9 cases with genetic data, the fusion partner was BRD4 (n=7), non-BRD4/3 (n=1), or undetermined (n=1). None of 306 carcinomas spanning the spectrum of salivary carcinoma types screened by NUT immunohistochemistry was positive. This is the first small series on salivary NC highlighting the importance to include this rare disease in the differential diagnosis of poorly differentiated salivary gland carcinomas and in cases of presumable poorly differentiated carcinoma of unknown origin.

NUT midline carcinoma of the head and neck: current perspectives

Abstract: NUT midline carcinoma (NMC) is a rare and aggressive subtype of squamous carcinoma that typically arises from midline supradiaphragmatic structures, frequently from the head and neck area. NMC is genetically driven by a chromosomal rearrangement involving the NUT gene, which forms oncoproteins considered major pathogenic drivers of cellular transformation. Diagnosis of NMC has been made remarkably easier with the availability of a commercial antibody against NUT, and can be established through positive nuclear immunohistochemical staining. Although NMC remains an underrecognized malignancy, in recent years there has appeared to be increasing awareness of disease and frequency of diagnosis in adults. To date, a standard treatment for head and neck NMC has not been established and a multimodal approach with systemic chemotherapy, surgery and radiation therapy is currently adopted in clinical practice. Recently, BET inhibitors and histone deacetylase inhibitors have emerged as two promising classes of targeted agents, currently investigated in clinical trials for adults with head and neck NMC. At the same time, combination approaches and novel targeted agents, such as next-generation BET inhibitors and CDK9 inhibitors, have shown preclinical activity. The present review explores the clinical pathological characteristics of NMC of the head and neck and presents the current state of the art on diagnosis, prognosis, and treatment of this rare but lethal disease.

Imaging Review of New and Emerging Sinonasal Tumors and Tumor-Like Entities from the Fourth Edition of the World Health Organization Classification of Head and Neck Tumors

The sinonasal tract is an environment diverse with neoplasia. Given the continued discovery of entities generally specific to the sinonasal tract, the fourth edition of the World Health Organization Classification of Head and Neck Tumors was released in 2017. It describes 3 new, well-defined entities and several less-defined, emerging entities. The new entities are seromucinous hamartomas, nuclear protein in testis carcinomas, and biphenotypic sinonasal sarcomas. Emerging entities include human papillomavirus-related sinonasal carcinomas, SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1-deficient sinonasal carcinomas, renal cell-like adenocarcinomas, and chondromesenchymal hamartomas. The literature thus far largely focuses on the pathology of these entities. Our goal in this report was to familiarize radiologists with these new diagnoses and to provide available information regarding their imaging appearances.

A 47-year-old woman with nuclear protein in testis midline carcinoma masquerading as a sinus infection: a case report and review of the literature

BACKGROUND

Nuclear protein in testis midline carcinoma is a rare, highly metastatic undifferentiated carcinoma that typically arises in midline structures and is characterized by having a fusion involving the nuclear protein in testis, NUT, gene. Nuclear protein in testis midline carcinoma has been identified in patients of all ages and is often initially misdiagnosed due to the rapid timeline of symptom onset.

CASE PRESENTATION

Here we report the case of a 47-year-old Caucasian woman with a nuclear protein in testis midline carcinoma that was initially mistaken for a sinus infection. After symptom progression while on an aggressive antibiotic regimen, the source of her symptoms was correctly identified as a sella mass. Comprehensive analysis of the tumor was performed, and standard cytogenetic analysis identified a translocation of 15q and 19p. Further testing identified a NUT-BRD4 fusion and confirmed the diagnosis of nuclear protein in testis midline carcinoma. Despite definitive diagnosis and surgical, radiation, and, ultimately, systemic therapy, she progressed rapidly, developing widespread metastases, and ultimately died from the disease 5 months after diagnosis.

CONCLUSIONS

Based on this and other previous reports, aggressive therapy should be initiated once nuclear protein in testis midline carcinoma is diagnosed and close surveillance employed in an attempt to prevent and/or recognize metastases as early as possible. Aggressive therapy has shown little efficacy such that the average overall survival for patients with nuclear protein in testis midline carcinoma is very short, often less than 6 months. Thus, early enrollment into clinical trials testing novel therapies for the treatment of nuclear protein in testis midline carcinoma should be considered. Finally, additional reports of nuclear protein in testis midline carcinoma are needed to fully characterize this rare and highly aggressive cancer.

SMARCB1 (INI1)-deficient sinonasal carcinoma: a series of 13 cases with assessment of histologic patterns

A significant proportion of sinonasal malignancies comprise poorly differentiated/undifferentiated carcinomas that defy accurate histologic classification and behave aggressively. Recent years have seen a refinement of this spectrum by inclusion of novel entities harboring specific genetic alterations, including SMARCB1 (INI1)-deficient sinonasal carcinoma (SDSC), characterized by inactivating alterations in SMARCB1 gene, as demonstrated by loss of INI1 immunoexpression. Cyclin D1 is a cell-cycle regulatory protein downstream of INI1. Loss of INI1 leads to derepression of cyclin D1 transcription, suggesting its role as a putative therapeutic target. However, cyclin D1 expression has not been assessed in SDSCs. We retrieved all sinonasal carcinomas, including sinonasal undifferentiated carcinoma, undifferentiated carcinoma, poorly differentiated squamous cell carcinoma, and adenocarcinoma. Histopathologic features were reviewed. INI1 immunohistochemistry was performed. Cyclin D1 was performed in cases showing INI1 loss. Loss of INI1 staining was seen in 13 cases (5.8%), including 11 males and 2 females (age range, 11-65 years). Original diagnoses included SDSC (3/13), sinonasal undifferentiated carcinoma (3/13), adenocarcinoma (3/13), poorly differentiated squamous cell carcinoma (2/13), and poorly differentiated carcinoma (2/13). Tumors were predominantly basaloid in 6 cases and plasmacytoid/rhabdoid in 5 cases. We identified 2 cases having oncocytoid cells arranged in a gland-like pattern. Significant cyclin D1 immunoexpression was absent. SDSC is a rare, emerging entity that resembles a poorly differentiated carcinoma. Histomorphologic spectrum of these tumors is evolving. In addition to basaloid and plasmacytoid/rhabdoid cells, oncocytoid/adenocarcinoma-like pattern can also be seen in SDSC and predicts INI1 loss. These histologic patterns can further be subjected to INI1 immunohistochemistry for correct diagnosis.

Small Cell Neuroendocrine Carcinoma: A Rare Nasopharyngeal Malignancy with Aggressive Clinical Course

Primary small cell neuroendocrine carcinoma is uncommon in head and neck region, with occasional cases in nasopharynx. Distinction from other round cell tumors is imperative to ensure optimal patient management. We present a case of a 30-year-old woman who presented with a rapidly growing nasopharyngeal mass.