SWI/SNF-deficient head and neck neoplasms: An overview

Teratocarcinosarcoma of the nasal cavity: challenges in the clinico-pathologic perspectives

OBJECTIVE

Clinicopathologic illustration of sinonasal teratocarcinosarcoma (SNTCS) in a middle-aged man, highlighting the difficulties and challenges encountered during surgical intervention, histopathologic diagnosis, and its overall management.

METHODOLOGY

Case report and literature review.

RESULTS

A 40-year-old man having recurrent epistaxis for three months presented with a dark-colored protruding polypoid nasal mass. Magnetic resonance imaging revealed a large, heterogeneous gadolinium-enhanced infiltrative lesion in the left nasal cavity with a T2-hypointense trans-septal zone. The mass abutted the cribriform plate, lamina papyracea, and septum, involved the inferior and middle turbinates, and blocked the choanae through the nasopharynx. There was profuse hemorrhage when an endoscope-assisted biopsy was attempted. Histopathology from the debulked specimen suggested SNTCS. The diagnosis was confirmed on immunohistochemistry. A metastatic search turned negative. However, at three weeks, the patient returned with a recurrence. A repeat debulking was done, and he was thereafter put on adjuvant chemotherapy. A second recurrence/residual lesion was noted midway through the chemotherapy regimen. However, it resolved after completion of the chemotherapy and subsequent image-guided radiotherapy, and the patient continued to be disease-free till the last follow-up at six weeks postradiotherapy.

CONCLUSIONS

SNTCS is an extremely aggressive malignancy that is seldom encountered in routine otolaryngology and pathology practice, with only a few reports of SNTCS documented. It is histologically composed of epithelial, mesenchymal, and primitive neuroectodermal elements with areas of undifferentiation. They are notorious for troublesome intra-operative bleeding, making complete surgical excision difficult, and the absence of a tumor-free margin often results in recurrence. Owing to their variegated and heterogeneous tissue composition, histopathologic diagnosis is enormously challenging without a representative tissue sample and immunohistochemistry. In spite of prompt and energetic multimodality treatment, survival rate is dismal.

SMARCB1-deficient Sinonasal Carcinoma: Expanding the Pathologic Spectrum With a Series of 32 Cases

SMARCB1-deficient sinonasal carcinoma (SDSC) is a recently recognized rare malignancy. Despite growing awareness, SDSC remains susceptible to misdiagnosis owing to its rarity and overlapping features with diverse mimics. A retrospective review of the clinical and pathologic features of 32 SDSC including 4 SMARCB-1 deficient adenocarcinoma (SDAC) cases was performed. The patients were aged 19 to 76 years with a male predominance. Most tumors arose in the naso-ethmoid (75%), and advanced stage (93.6%), with frequent multi-sinus (90.5%) involvement. Histologically, tumors exhibited diverse morphologies, including basaloid (50%), rhabdoid (25%), and undifferentiated (12.5%) types. SDAC cases showed glandular differentiation with intraluminal and stromal mucin. Empty vacuoles (62.5%), pagetoid spread (31.3%), eosinophilic-granular bodies (18.8%), hyaline globules (15.2%), and florid glomeruloid neovascularization (15.6%) were additional findings. Yolk sac-like areas were encountered in 18.6%. Immunohistochemically, tumors were defined by a complete loss of SMARCB1 (100%); a variable reactivity for p40 (65.6%), synaptophysin (13.6%), glypican3 (6.1%), and CD34 (6.1%) was present. Notably, >90% of our patients had different initial diagnoses before referral. Lymph node metastasis, locoregional recurrence, and distant metastasis were seen in 23.3%, 24.1%, and 27.6% patients, respectively; 37.9% died of disease. In conclusion, SDSCs are rare and aggressive sinonasal malignancies that display a wide histologic spectrum including glandular differentiation. This study expands on the morphologic spectrum of SDSC by analyzing a large cohort of 32 cases, adding comprehensive clinical, histopathologic, and immunohistochemical data, and highlighting features to improve diagnostic accuracy. The emergence of targeted therapies, such as EZH2 inhibitors, further underscores the importance of accurate diagnosis.

Delayed Diagnosis of SMARCA4-Deficient Undifferentiated Tumor in a Heavy Smoker Male Patient: Discovered Through Bone Sampling, with Extensive Distant Metastases and Concurrent Granulomatous Disease, Leading to Patient Fatality

Background. SMARCA4-deficient undifferentiated tumors are rare and pose a diagnostic challenge. This study delves into the intricate diagnostic terrain of SMARCA4-deficient undifferentiated tumors, providing insights into their diverse clinical presentations and diagnostic approaches. Case Presentation. A 69-year-old heavy-smoker man with adalimumab-treated rheumatoid arthritis presented with multiple lesions. A CT scan revealed a spiculated lung mass, enlarged mediastinal lymph nodes, and hepatic lesions. A whole-body FDG-PET/CT scan revealed heterogeneous hypermetabolic lesions in the lung, liver, and bone. Initial two core needle liver biopsies and a left upper lobe lung wedge resection initially indicated steatohepatitis and granulomatous formation with no evidence of malignancy. Several months later, the patient returned with left-sided flank pain and significant weight loss. CT scan identified a thigh mass, adrenal lesion, and extensive multiple skeletal lesions. A biopsy of the thigh mass revealed an extensively necrotic, epithelioid-to-spindled cell neoplasm with positive staining for pan keratin, focal staining for CD56, and a loss of nuclear expression of SMARCA4. A final diagnosis of SMARCA4-deficient undifferentiated tumor was rendered. Unfortunately, the patient's condition deteriorated, and he died a few weeks after receiving the final diagnosis. Conclusion. SMARCA4-deficient undifferentiated tumors have emerged as recent subjects of medical study, distinguished by their unique morphology and SMARCA4-deficient immunohistochemistry. These tumors present diverse clinical manifestations, affecting multiple organ systems. This report underscores the diagnostic complexities associated with complex clinical presentation and highlights the importance of multidisciplinary collaboration in addressing challenging clinical scenarios, particularly among heavy smoker male patients and intricate radiological presentations.

Intestinal Type Sinonasal Adenocarcinoma: A Clinicopathological Study of 48 Patients With Review of Literature

BACKGROUND

Intestinal type sinonasal adenocarcinoma is a gland forming malignant tumor of sinonasal tract which is histologically and immunohistochemically similar to intestinal type adenocarcinomas. Intestinal type sinonasal adenocarcinoma has a well-recognized etiological association with occupational exposure to wood dusts.

OBJECTIVE

To report the clinicopathological factors of intestinal type sinonasal adenocarcinoma and review the published literature.

METHODS

Forty-eight tumors reported as intestinal type sinonasal adenocarcinoma were retrieved and clinicopathological features were noted.

RESULTS

Age ranged from 22 to 79 (mean 44) years with 36 men and 12 women. Most patients were presented with nasal blockage and difficulty in breathing. Occupational exposure to dust was present in the majority of patients. Tumors were composed of papillae or acini lined by dysplastic intestinal type columnar epithelium with interspersed goblet cells. There were 13 well differentiated (low grade) and 35 poorly differentiated (high-grade) tumors. CDX2 and SATB2 were expressed by the tumor cells in most tumors. Follow-up was available in 24 patients (range 3 months to 10 years). Most of the patients received chemo and/or radiotherapy. Metastases occurred in 19 out of 24 patients. Brain metastases were very common. All patients with metastases died of their disease.

CONCLUSION

Clinical and morphological features in our series were similar to published studies. It is important for pathologists to remember the association of these tumors with occupational exposure to wood dusts and to exclude metastases of intestinal adenocarcinomas when confronted by these tumors in the sinonasal tract.

Adaptive Treatment Strategy: Adjuvant Chemoradiotherapy for a Complex SMARCB1 (INI-1)-Deficient Sinonasal Carcinoma With Intracranial Extension

SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1 (SMARCB1) (integrase interactor 1)-deficient sinonasal carcinoma (SDSNC) is a rare and aggressive malignancy of the head and neck. It is characterised by the absence of nuclear SMARCB1 expression and typically presents at advanced stages due to non-specific symptoms resembling benign conditions such as nasal polyps or sinusitis. This report describes a 64-year-old male who presented with a sphenoidal sinus mass causing bony erosion and intracranial extension, associated with headaches and diplopia. Initial management included endoscopic debulking surgery, followed by chemoradiotherapy to address residual disease in proximity to the optic chiasm and brainstem. Urgent radiotherapy was delivered using volumetric-modulated arc therapy, with a total dose of 66 Gy, requiring precise sparing of critical structures. Immunohistochemical analysis confirmed SMARCB1 deficiency. Post-treatment imaging revealed significant tumour volume reduction, and immune checkpoint inhibitor therapy was initiated for disease control. At five months post-treatment, the tumour remained stable. This case highlights the diagnostic and therapeutic challenges of SDSNC, particularly in cases involving critical anatomic structures. It demonstrates the importance of multidisciplinary treatment strategies, advanced radiotherapy planning, and immunotherapy in optimising outcomes for this rare malignancy.

Switch/Sucrose Non-Fermentable (SWI/SNF) Complex-Partial Loss in Sinonasal Squamous Cell Carcinoma: A High-Grade Morphology Impact and Progression

Sinonasal carcinomas are aggressive neoplasms that present a high morbidity and mortality rate with an unfavorable prognosis. This group of tumors exhibits morphological and genetic diversity. Genetic and epigenetic alterations in these neoplasms are the current targets for diagnosis and treatment. The most common type of cancer originating in the sinonasal tract is sinonasal squamous cell carcinomas (SNSCCs), which present different histological patterns and variable histological aggressiveness. A significant number of alterations have been reported in sinonasal tumors, including deficiencies in the Switch/Sucrose non-fermentable (SWI/SNF) chromatin remodeling complex. In the sinonasal tract, deficiencies of the subunits SMARCB1/INI1, SMARCA4/BRG1, and SMARCA2 have been noted in carcinomas, adenocarcinomas, and soft tissue tumors with a distinctive high-grade morphology and a fatal prognosis.

OBJECTIVE

The objective of this study is to identify the status of the SWI/SNF complex using immunohistochemistry in sinonasal squamous cell carcinomas and their association with morphology and survival.

METHODS

A total of 103 sinonasal carcinomas with different grades of squamous differentiation were analyzed; the selection was based on those cases with high-grade morphology. The carcinomas were then evaluated immunohistochemically for SMARCB1 and SMARCA4 proteins. Their expression was compared with the biological behavior and survival of the patients.

RESULTS

Among the SNSCCs, 47% corresponded to the non-keratinizing squamous cell carcinoma (NKSCC) type with high-grade characteristics, 40% were keratinizing squamous cell carcinomas (KSCCs), 9% were SMARCB1-deficient carcinomas, and 4% were SMARCA4-deficient carcinomas. Mosaic expression for SMARCB1 (NKSCC-33%; KSCC-21.9%) and SMARCA4 (NKSCC-14.6%; KSCC-12.2%) was identified, showing an impact on tumor size and progression.

CONCLUSIONS

We identified that that the partial loss (mosaic expression) of SMARCB1 in SNSCCs is associated with high-grade malignant characteristics and a negative effect on patient survival; meanwhile, SMARCA4-mosaic expression in SNSCCs is associated with high-grade malignant characteristics and an increase in tumor size concerning the intact SMARCA4.

Update on Sinonasal Tract Malignancies: Advances in Diagnostic Modalities

CONTEXT.—

Sinonasal tract malignancies are rare cancers with frequent morphologic overlap. Given the similar histologic profiles seen in many of these entities, they often present a diagnostic challenge to the practicing pathologist.

OBJECTIVE.—

To provide a streamlined algorithm using histologic clues, immunohistochemical profiles, and molecular assays to aid in diagnosis of these lesions.

DATA SOURCES.—

Sources were the World Health Organization Tumor Classification, literature review, and institutional experience.

CONCLUSIONS.—

Although many sinonasal tract malignancies show similar histology, distinct immunohistochemical and molecular profiles can help parse out differences, thereby facilitating diagnosis for the pathologist.

SMARCB1 (INI-1) deficient sinonasal carcinoma of the right maxillary sinus - A rare entity

INTRODUCTION AND IMPORTANCE

SMARCB1 (INI-1) is a vital tumour suppressor gene on chromosome 22q11.2, preventing tumour development in the SWI/SNF complex. Mutations cause SMARCB1-deficient tumours with distinct features. Loss of INI-1 expression is seen in malignancies, including sinonasal carcinoma and atypical teratoid/rhabdoid tumours. Recently recognized as a separate entity, SMARCB1-deficient sinonasal carcinomas (SDSC) are rare, clinically aggressive, and mimic other malignancies, emphasizing their significant diagnosis due to poorer prognosis, particularly in the elderly.

CASE PRESENTATION

A 66-year-old male presented with a 4-month-old right cheek swelling, diagnosed initially as a sinonasal neoplastic mass. The biopsy revealed sinonasal mucosal fragments infiltrated by a tumour with plasmacytoid morphology. Immunohistochemistry (IHC) of the tumour cells was positive for p63 and pan-cytokeratin and showed INI-1 loss. Subsequent subtotal maxillectomy was performed, and the patient received adjuvant chemotherapy and radiotherapy. At a thirteen-month follow-up, the patient achieved his daily activities with no signs of recurrence.

CLINICAL DISCUSSION

The loss of protein expression in sinonasal cancer is predominantly attributed to the homozygous deletion of SMARCB1. SDSC, a profoundly invasive malignant carcinoma, tends to infiltrate sinuses and extend into the intracranial regions. The IHC findings of our case were in coherence with previous studies in SMARCB1. The prognosis is particularly unfavourable in males and advanced tumours.

CONCLUSION

The tumour's microscopic and immunohistochemical characteristics indicated the SDSC. Due to its aggressive nature and high mortality rates, dealing with a paranasal mass, one should be suspicious of this tumour.

Malignant Rhabdoid Tumor and Related Pediatric Tumors: Multimodality Imaging Review with Pathologic Correlation

Malignant rhabdoid tumors (MRTs) are rare but lethal solid neoplasms that overwhelmingly affect infants and young children. While the central nervous system is the most common site of occurrence, tumors can develop at other sites, including the kidneys and soft tissues throughout the body. The anatomic site of involvement dictates tumor nomenclature and nosology. While the clinical and imaging manifestations of MRTs and other more common entities may overlap, there are some site-specific distinctive imaging characteristics. Irrespective of the site of occurrence, somatic and germline mutations in SMARCB1, and rarely in SMARCA4, underlie the entire spectrum of rhabdoid tumors. MRTs have a simple and remarkably stable genome but can demonstrate considerable molecular and biologic heterogeneity. Related neoplasms encompass an expanding category of phenotypically dissimilar (nonrhabdoid tumors driven by SMARC-related alterations) entities. US, CT, MRI, and fluorodeoxyglucose PET/CT or PET/MRI facilitate diagnosis, initial staging, and follow-up, thus informing therapeutic decision making. Multifocal synchronous or metachronous rhabdoid tumors occur predominantly in the context of underlying rhabdoid tumor predisposition syndromes (RTPSs). These autosomal dominant disorders are driven in most cases by pathogenic variants in SMARCB1 (RTPS type 1) and rarely by pathogenic variants in SMARCA4 (RTPS type 2). Genetic testing and counseling are imperative in RTPS. Guidelines for imaging surveillance in cases of RTPS are based on age at diagnosis. ©RSNA, 2024 Supplemental material is available for this article.

Primary Oropharyngeal SMARCA4-Deficient Carcinoma: Expanding the Diagnostic Spectrum in Head and Neck Cancer

With the advent of molecular immunohistochemistry and next generation sequencing, Switch/sucrose non-fermentable (SWI/SNF) chromatin remodeling complex altered tumors have gained recognition recently. SWI/SNF related, matrix associated, actin dependent regulator of chromatin subfamily B member 1 (SMARCB1) and SMARCA4 are the primary SWI/SNF components altered in several recently described undifferentiated malignancies in head and neck region with predilection for paranasal sinuses in SMARCB1-deficient tumors and nasal cavity in SMARCA4-deficient tumors. However, to the best of our knowledge, SMARCA4-deficient tumors of the oropharynx have not been described. We present an unusual case of SMARCA4-deficient carcinoma of the oropharynx (palatine tonsil) which is the first case in the literature, expanding the topographic distribution of SMARCA4-deficient tumors in the head and neck region and emphasizing the importance of BRG1 as an essential immunohistochemical marker for the diagnosis of this distinct entity.

ARID1A loss is associated with increased NRF2 signaling in human head and neck squamous cell carcinomas

Prior to the next generation sequencing and characterization of the tumor genome landscape, mutations in the SWI/SNF chromatin remodeling complex and the KEAP1-NRF2 signaling pathway were underappreciated. While these two classes of mutations appeared to independently contribute to tumor development, recent reports have demonstrated a mechanistic link between these two regulatory mechanisms in specific cancer types and cell models. In this work, we expand upon these data by exploring the relationship between mutations in BAF and PBAF subunits of the SWI/SNF complex and activation of NRF2 signal transduction across many cancer types. ARID1A/B mutations were strongly associated with NRF2 transcriptional activity in head and neck squamous carcinomas (HNSC). Many additional tumor types showed significant association between NRF2 signaling and mutation of specific components of the SWI/SNF complex. Different effects of BAF and PBAF mutations on the polarity of NRF2 signaling were observed. Overall, our results support a context-dependent functional link between SWI/SNF and NRF2 mutations across human cancers and implicate ARID1A inactivation in HPV-negative HNSC in promoting tumor progression and survival through activation of the KEAP1-NRF2 signaling pathway. The tumor-specific effects of these mutations open a new area of study for how mutations in the KEAP1-NRF2 pathway and the SWI/SNF complex contribute to cancer.

International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors

BACKGROUND

Sinonasal neoplasms, whether benign and malignant, pose a significant challenge to clinicians and represent a model area for multidisciplinary collaboration in order to optimize patient care. The International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors (ICSNT) aims to summarize the best available evidence and presents 48 thematic and histopathology-based topics spanning the field.

METHODS

In accordance with prior International Consensus Statement on Allergy and Rhinology documents, ICSNT assigned each topic as an Evidence-Based Review with Recommendations, Evidence-Based Review, and Literature Review based on the level of evidence. An international group of multidisciplinary author teams were assembled for the topic reviews using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses format, and completed sections underwent a thorough and iterative consensus-building process. The final document underwent rigorous synthesis and review prior to publication.

RESULTS

The ICSNT document consists of four major sections: general principles, benign neoplasms and lesions, malignant neoplasms, and quality of life and surveillance. It covers 48 conceptual and/or histopathology-based topics relevant to sinonasal neoplasms and masses. Topics with a high level of evidence provided specific recommendations, while other areas summarized the current state of evidence. A final section highlights research opportunities and future directions, contributing to advancing knowledge and community intervention.

CONCLUSION

As an embodiment of the multidisciplinary and collaborative model of care in sinonasal neoplasms and masses, ICSNT was designed as a comprehensive, international, and multidisciplinary collaborative endeavor. Its primary objective is to summarize the existing evidence in the field of sinonasal neoplasms and masses.

Sinonasal DEK-rearranged Papillary Non-keratinizing Squamous Cell Carcinoma: Expanding the Emerging Entity

The newly emerging sinonasal carcinomas have demonstrated diverse morphologies and specific molecular mutations along with deviant clinical behavior from conventional counterparts. Also, many sinonasal malignancies turned to be SMARCB1/SMARCA4-deficient. Even with the morphological similarities between poorly differentiated (non) keratinizing sinonasal squamous cell carcinoma (SNSCC) from DEK::AFF2 SNSCC, the two lesions are not distinguishable using the surrogate immunohistochemical marker AFF2 or molecular testing for DEK::AFF2 mutation. We report a rare case of SMARCB1-retained DEK-rearranged papillary non-keratinizing SNSCC in a 53-year-old female, who presented with a polypoid mass corresponding to the left middle turbinate. The tumor and locoregional lymph nodes were surgically resected, followed by adjuvant radiotherapy.

Diagnostic and Treatment-Related Challenges in Sinonasal Teratocarcinosarcoma: A Report of Three Cases

Background

Sinonasal teratocarcinosarcoma is a rare, aggressive malignancy located almost exclusively in the nasal cavity, paranasal sinuses, or anterior skull base. Histopathological diagnosis can be challenging due to the heterogeneous composition.

Methods

Retrospective analysis of 3 patients with sinonasal teratocarcinosarcoma diagnosed and treated at the University Medical Center Utrecht was conducted.

Results

Patients presented with nasal obstruction, epistaxis, headaches, or behavioral changes. All three patients had locally advanced disease, and one had lymph node metastases. Two patients underwent surgery followed by radiotherapy, and one underwent neoadjuvant chemotherapy followed by surgery. The follow-up duration ranged from 3 to 32 months. All three patients died due to progression of their disease.

Conclusion

Sinonasal teratocarcinosarcoma is characterized by rapid, aggressive local expansion. The prognosis is poor due to a high risk of metastases and locally recurrent disease. Multimodality treatment consisting of surgery, followed by (chemo)-radiotherapy, is essential for optimizing outcomes. Neoadjuvant therapy offers a promising treatment option.

Teratocarcinosarcoma of the head and neck: Clinicopathologic review of a rare entity

Teratocarcinosarcoma is a rare, highly aggressive malignancy of the head and neck, characterized by multiphenotypic and triphasic growth of epithelial, mesenchymal, and primitive neuroepithelial elements. Owing to its rarity and morphological heterogeneity, as well as the lack of experience with this neoplasm, teratocarcinosarcoma is often misdiagnosed, particularly in small biopsy samples when only some of the elements are identified, thus leading to delayed management. Aggressive clinical behavior and poor survival outcomes, necessitate an accurate diagnosis and appropriate treatment. This review describes the main demographic and clinicopathological features of teratocarcinosarcoma, with an emphasis on the recent advances that have attempted to identify the molecular signature of this neoplasm.

Diagnostic algorithm for challenging blue cell sinonasal carcinoma

The newly emerging sinonasal carcinomas have demonstrated diverse morphologies and specific molecular rearrangements along with deviant clinical behavior from conventional counterparts. We aim to propose a diagnostic algorithm that is based on molecular findings of each sinonasal cancer and is considering the new entities has been called upon. Such a diagnostic algorithm should help diagnostic pathologists establish a diagnosis of a challenging sinonasal blue cell carcinomas and researchers performing retrospective analysis of archival cases. Along with consulting our archival cases, literature mining was conducted to retrieve the immunohistochemical and molecular findings regarding the newly emerging entities. Our proposed algorithm distinguishes poorly differentiated (non) keratinizing SNSCC, from anaplastic myoepithelial carcinoma, NUT midline carcinoma, SMARCB1/SMARCA4-deficient teratocarcinosarcoma, SMARCB1/SMARCA4-deficient carcinosarcoma, olfactory neuroblastoma, sinonasal undifferentiated carcinoma, HPV-related multiphenotypic sinonasal carcinoma and other adenocarcinomas. By incorporating morphologic features, immunohistochemical markers, and molecular investigations, the algorithm enhances the accuracy of diagnosis, particularly in cases where comprehensive molecular testing is not readily available. This algorithm serves as a valuable resource for pathologists, facilitating the proper diagnosis of sinonasal malignancies and guiding appropriate patient management.

Top 10 Histological Mimics of Neuroendocrine Carcinoma You Should Not Miss in the Head and Neck

BACKGROUND

The spectrum of neuroendocrine neoplasia (NEN) of the head and neck region is wide-ranging and diverse, including a variety of diagnoses stretching from benign and low-malignant tumor forms to highly proliferative, poor prognosis neuroendocrine carcinoma (NEC). Moreover, there are several non-neuroendocrine differential diagnoses to keep in mind as well, displaying various degree of morphological and/or immunohistochemical overlap with bona fide neuroendocrine lesions.

METHODS

Review.

RESULTS

While the growth patterns may vary, well-differentiated NEN usually display a stippled "salt and pepper" chromatin, a granular cytoplasm, and unequivocal expression of neuroendocrine markers such as chromogranin A and synaptophysin. However, these features are often less pronounced in NEC, which may cause diagnostic confusion-not the least since several non-NEC head and neck tumors may exhibit morphological similarities and focal neuroendocrine differentiation.

CONCLUSION

As patients with NEC may require specific adjuvant treatment and follow-up, knowledge regarding differential diagnoses and potential pitfalls is therefore clinically relevant. In this review, the top ten morphological and/or immunohistochemical mimics of NEC are detailed in terms of histology, immunohistochemistry, and molecular genetics.

Top 10 Basaloid Neoplasms of the Sinonasal Tract

BACKGROUND

Basaloid neoplasms of the sinonasal tract represent a significant group of tumors with histological overlap but often with different etiologies (i.e., viral, genetics), clinical management, and prognostic significance.

METHODS

Review.

RESULTS

"Basaloid" generally refers to cells with coarse chromatin in round nuclei and sparse cytoplasm, resembling cells of epithelial basal layers or imparting an "immature" appearance. Tumors with this characteristic in the sinonasal tract are represented by a spectrum of benign to high-grade malignant neoplasms, such as adenoid cystic carcinoma, NUT carcinoma, sinonasal undifferentiated carcinoma, SWI/SNF complex-deficient carcinomas, and adamantinoma-like Ewing sarcoma.

CONCLUSION

In some instances, histology alone may be sufficient for diagnosis. However, limited biopsy material or fine-needle aspiration specimens may be particularly challenging. Therefore, often other diagnostic procedures, including a combination of histology, immunohistochemistry (IHC), DNA and RNA testing, and molecular genetics are necessary to establish an accurate diagnosis.

SWI/SNF-deficient Sinonasal Carcinomas

The classification of poorly differentiated sinonasal carcinomas and their nonepithelial mimics has experienced tremendous developments during the last 2 decades. These recent developments paved the way for an increasingly adopted approach to a molecular-based or etiology-based refined classification of the many carcinoma variants that have been historically lumped into the sinonasal undifferentiated carcinoma category. Among these new achievements, recognition of carcinoma subtypes driven by defects in the Switch/Sucrose nonfermentable (SWI/SNF) chromatin remodeling complex represents a major highlight. This resulted in a new definition of 4 sinonasal entities driven solely or predominantly by Switch/Sucrose nonfermentable complex deficiency: (1) SMARCB1(INI1)-deficient sinonasal carcinoma (lacking gland formation and frequently displaying a non-descript basaloid, and less frequently eosinophilic/oncocytoid morphology, but no features of other definable subtypes), (2) SMARCB1-deficient sinonasal adenocarcinoma (with unequivocal glands or yolk sac-like pattern), (3) SMARCA4-deficient undifferentiated (sinonasal undifferentiated carcinoma-like) carcinoma (lacking glandular or squamous immunophenotypes), and (4) SMARCA4-deficient subset (~80%) of sinonasal teratocarcinosarcoma. Fortunately, diagnostic loss of all these proteins can be detected by routine immunohistochemistry, so that genetic testing is not mandatory in routine practice. This review summarizes the main demographic, clinicopathological, and molecular features of these new entities.

Unclassified Neuroendocrine Tumor with a Novel CHD4::AFF2 Fusion: Expanding the Family of AFF2-Rearranged Head and Neck Malignancies

The past decade has seen a dramatic increase in the number of new head and neck tumor entities, most of which are genetically defined. DEK::AFF2 carcinoma is one of the most recently defined neoplasms; it shows a non-keratinizing squamous morphology and occurs in the sinonasal region. We present an unusual neoplasm that was found to harbor a novel fusion involving AFF2. The case was encountered in our clinical practice. Immunohistochemistry was performed along with targeted next generation sequencing (NGS). The case presented as a metastasis to a cervical lymph node from an unknown primary, in a 49-year-old man. The tumor consisted of sheets of primitive round cells which were strongly positive for synaptophysin and chromogranin but negative for cytokeratins, S-100 protein, WT-1, desmin, and many other markers. NGS uncovered CHD4::AFF2. We found a CHD4::AFF2 fusion in a high-grade neuroendocrine tumor. Although it is just a single case, the presence of a novel fusion in a neoplasm that is otherwise not classifiable suggests that it could be a distinct entity within a possible family of AFF2-rearranged tumors. Molecular analysis should be considered for any unclassified round cell tumor in the head and neck, as additional cases will be needed to further elucidate this area.

Adamantinoma-Like Ewing Sarcoma of the Head and Neck: A Case-Series of a Rare and Challenging Diagnosis

Adamantinoma-like Ewing sarcoma (ALES) is a rare malignant tumor characterized by EWSR1::FLI1 related fusions and complex epithelial differentiation. ALES poses a tremendous diagnostic challenge owing to its resemblance to a wide variety of common head and neck malignancies. We aimed to study the clinicopathologic spectrum of ALES diagnosed at our institute. A retrospective review of the clinical and pathologic features of all EWSR1-rearranged ALES cases was performed after confirming the diagnosis. The cases lacking EWSR1 rearrangement were excluded. A total of 7 patients were analyzed. The median age was 27 years (range 7-42 years). There were 4 males and 3 female patients. Tumors were distributed as follows: maxilla (n = 2), parotid (n = 2), nasal cavity (n = 1), ethmoid/maxilla (n = 1), and thyroid (n = 1). Tumor size ranged from 2.2 to 5.5 cm. On microscopy, tumors displayed nested-lobular architecture, monomorphic cells, and interlobular fibrotic stroma. Other features included: palisading (n = 5), squamous differentiation (n = 2), keratinization (n = 1), colonisation of salivary ducts (n = 1) and thyroid follicles (n = 1), follicle-like cysts (n = 3), calcification (n = 2), necrosis (n = 3). Mitotic rate was 4-15/2 mm2. On immunohistochemistry, cytokeratins (100%), p40 (100%), strong/diffuse membranous CD99 (100%), NKX2.2 (100%), Fli-1 (71%), and synaptophysin (71%) was positive. Patients received chemotherapy (n = 7) and radiotherapy (n = 4). Two patients developed recurrence at 6 and 10 months; 3 developed metastases at 0, 6, and 25 months. ALES is a rare and aggressive malignancy that mimics diverse neoplasms common in the head and neck region. Awareness of the morphologic and immunohistochemistry spectrum of this tumor is essential to avoid diagnostic errors.

SMARCB1 (INI-1)-Deficient Sinonasal Carcinoma: A Systematic Review and Pooled Analysis of Treatment Outcomes

(1) Background: SMARCB1 (INI-1)-deficient sinonasal carcinoma is a rare sinonasal malignancy; since its discovery and description in 2014, less than 200 cases have been identified. It is almost impossible to perform randomized-controlled trials on novel therapy to improve treatment outcomes in view of its rarity. We performed a systematic review of all the published case reports/series and included our patients for survival analysis. (2) Methods: In this systematic review, we searched from PubMed-MEDLINE, EMBASE, Scopus, Cochrane Library, CINAHL, and Google Scholar for individual patient data to identify and retrieve all reported SMARCB1-deficient sinonasal carcinoma. Clarification on treatment details and the most updated survival outcomes from all authors of the published case reports/series were attempted. Survival analysis for overall survival (OS) and identification of OS prognostic factors were performed. This systematic review was registered with PROSPERO (CRD42022306671). (3) Results: A total of 67 publications were identified from the systematic review and literature search. After excluding other ineligible and duplicated publications, 192 patients reported were considered appropriate for further review. After excluding duplicates and patients with incomplete pretreatment details and survival outcomes, 120 patients were identified to have a complete set of data including baseline demographics, treatment details, and survival outcomes. Together with 8 patients treated in our institution, 128 patients were included into survival analysis. After a median follow up of 17.5 months (range 0.3-149.0), 50 (46.3%) patients died. The 1-year, 2-year and 3-year OS rates were 84.3% (95% CI % 77.6-91.0), 62.9% (95% CI 53.1-72.7), and 51.8% (95% CI 40.8-62.8), respectively, and the median OS was 39.0 months (95% CI 28.5-49.5). Males (p = 0.029) and T4b disease (p = 0.013) were significant OS prognostic factors in univariable analysis, while only T4b disease (p = 0.017) remained significant in multivariable analysis. (4) Conclusions: SMARCB1-deficient sinonasal carcinoma is an extremely aggressive sinonasal malignancy with a dismal prognosis. Early diagnosis and a multimodality treatment strategy are essential for a better treatment and survival outcome.

Proceedings of the North American Society of Head and Neck Pathology, Los Angeles, CA, March 20, 2022: SWI/SNF-deficient Sinonasal Neoplasms: An Overview

The pathology of poorly differentiated sinonasal malignancies has been the subject of extensive studies during the last decade, which resulted into significant developments in the definitions and histo-/pathogenetic classification of several entities included in the historical spectrum of "sinonasal undifferentiated carcinomas (SNUC)" and poorly differentiated unclassified carcinomas. In particular, genetic defects leading to inactivation of different protein subunits in the SWI/SNF chromatin remodeling complex have continuously emerged as the major (frequently the only) genetic player driving different types of sinonasal carcinomas. The latter display distinctive demographic, phenotypic and genotypic characteristics. To date, four different SWI/SNF-driven sinonasal tumor types have been recognized: SMARCB1(INI1)-deficient carcinoma (showing frequently non-descript basaloid, and less frequently eosinophilic, oncocytoid or rhabdoid undifferentiated morphology), SMARCB1-deficient adenocarcinomas (showing variable gland formation or yolk sac-like morphology), SMARCA4-deficient carcinoma (lacking any differentiation markers and variably overlapping with large cell neuroendocrine carcinoma and SNUC), and lastly, SMARCA4-deficient sinonasal teratocarcinosarcoma. These different tumor types display highly variable immunophenotypes with SMARCB1-deficient carcinomas showing variable squamous immunophenotype, while their SMARCA4-related counterparts lack such features altogether. While sharing same genetic defect, convincing evidence is still lacking that SMARCA4-deficient carcinoma and SMARCA4-deficient teratocracinosarcoma might belong to the spectrum of same entity. Available molecular studies revealed no additional drivers in these entities, confirming the central role of SWI/SNF deficiency as the sole driver genetic event in these aggressive malignancies. Notably, all studied cases lacked oncogenic IDH2 mutations characteristic of genuine SNUC. Identification and precise classification of these entities and separating them from SNUC, NUT carcinoma and other poorly differentiated neoplasms of epithelial melanocytic, hematolymphoid or mesenchymal origin is mandatory for appropriate prognostication and tailored therapies. Moreover, drugs targeting the SWI/SNF vulnerabilities are emerging in clinical trials.

Towards a Molecular Classification of Sinonasal Carcinomas: Clinical Implications and Opportunities

Simple Summary

In recent years, there have been several molecular and immunohistochemical additions to the pathologic diagnosis of sinonasal malignancies that could facilitate the identification of clinically relevant groups of sinonasal malignancies. Molecular profiling is progressively integrated in the histopathologic classification of sinonasal carcinomas, and it is likely to influence the management of these tumors in the near future. In this article we review the recent literature on molecular analysis and/or subtyping of sinonasal carcinomas and we discuss the possible clinical implications of a classification of sinonasal tumors based on their molecular features.

Abstract

Sinonasal carcinomas are a heterogeneous group of rare tumors, often with high-grade and/or undifferentiated morphology and aggressive clinical course. In recent years, with increasing molecular testing, unique sinonasal tumor subsets have been identified based on specific genetic alterations, including protein expression, chromosomal translocations, specific gene mutations, or infection by oncogenic viruses. These include, among others, the identification of a subset of sinonasal carcinomas associated with HPV infection, the identification of a subset of squamous cell carcinomas with EGFR alterations, and of rare variants with chromosomal translocations (DEK::AFF2, ETV6::NTRK and others). The group of sinonasal adenocarcinomas remains very heterogeneous at the molecular level, but some recurrent and potentially targetable genetic alterations have been identified. Finally, poorly differentiated and undifferentiated sinonasal carcinomas have undergone a significant refinement of their subtyping, with the identification of several new novel molecular subgroups, such as NUT carcinoma, IDH mutated sinonasal undifferentiated carcinoma and SWI/SNF deficient sinonasal malignancies. Thus, molecular profiling is progressively integrated in the histopathologic classification of sinonasal carcinomas, and it is likely to influence the management of these tumors in the near future. In this review, we summarize the recent developments in the molecular characterization of sinonasal carcinomas and we discuss how these findings are likely to contribute to the classification of this group of rare tumors, with a focus on the potential new opportunities for treatment.

Atypical Teratoid Rhabdoid Tumours Are Susceptible to Panobinostat-Mediated Differentiation Therapy

Simple Summary

Atypical teratoid rhabdoid tumour (ATRT) is an aggressive undifferentiated malignancy of the central nervous system in children. A defining feature of ATRT is the loss of the SMARCB1 gene that is essential for regulating gene expression required for normal developmental processes. We show that treatment of human ATRT cell models with the histone deacetylate inhibitor, panobinostat, inhibits tumour growth, reactivates the expression of developmental genes, and drives neuronal differentiation. These results demonstrate the therapeutic potential of panobinostat for the treatment of ATRT.

Abstract

Atypical teratoid rhabdoid tumour (ATRT) is a rare but highly aggressive undifferentiated solid tumour arising in the central nervous system and predominantly affecting infants and young children. ATRT is exclusively characterized by the inactivation of SMARCB1, a member of the SWI/SNF chromatin remodelling complex that is essential for the regulation of large sets of genes required for normal development and differentiation. Histone deacetylase inhibitors (HDACi) are a promising anticancer therapy and are able to mimic the normal acetylation functions of SMARCB1 in SMARCB1-deficient cells and drive multilineage differentiation in extracranial rhabdoid tumours. However, the potential efficacy of HDACi in ATRT is unknown. Here, we show that human ATRT cells are highly responsive to the HDACi panobinostat and that sustained treatment leads to growth arrest, increased cell senescence, decreased clonogenicity and induction of a neurogenesis gene-expression profile. Furthermore, in an orthotopic ATRT xenograft model, continuous panobinostat treatment inhibits tumour growth, increases survival and drives neuronal differentiation as shown by the expression of the neuronal marker, TUJ1. Collectively, this preclinical study supports the therapeutic potential of panobinostat-mediated differentiation therapy for ATRT.

Qualitative and Quantitative Diagnosis in Head and Neck Cancer

The diagnosis is the art of determining the nature of a disease, and an accurate diagnosis is the true cornerstone on which rational treatment should be built. Within the workflow in the management of head and neck tumours, there are different types of diagnosis. The purpose of this work is to point out the differences and the aims of the different types of diagnoses and to highlight their importance in the management of patients with head and neck tumours. Qualitative diagnosis is performed by a pathologist and is essential in determining the management and can provide guidance on prognosis. The evolution of immunohistochemistry and molecular biology techniques has made it possible to obtain more precise diagnoses and to identify prognostic markers and precision factors. Quantitative diagnosis is made by the radiologist and consists of identifying a mass lesion and the estimation of the tumour volume and extent using imaging techniques, such as CT, MRI, and PET. The distinction between the two types of diagnosis is clear, as the methodology is different. The accurate establishment of both diagnoses plays an essential role in treatment planning. Getting the right diagnosis is a key aspect of health care, and it provides an explanation of a patient’s health problem and informs subsequent decision. Deep learning and radiomics approaches hold promise for improving diagnosis.

Recent updates in thoracic SMARCA4-deficient undifferentiated tumor

Germline inactivating mutations in SMARCA4 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 4) gene encoding for BRG1 (Brahma related gene-1) are the molecular drivers in small cell carcinoma of ovary, hypercalcemic type (SCCOHT) and in malignant rhabdoid tumors (MRT) that occur in the context of rhabdoid tumor predisposition syndrome-type 2. Somatic SMARCA4 mutations and/or loss of BRG1 have been identified in a variety of adult-onset epithelial and mesenchymal neoplasms. Among thoracic tumors, these include subsets of smoking-related non-small cell lung carcinoma (NSCLC) and a relatively rare, newly recognised tumor entity: thoracic SMARCA4-deficient undifferentiated tumor (SMARCA4-UT). Less than 100 cases of SMARCA4-UT have been reported to date. They present as large compressive and infiltrative mediastinal, lung and/or pleural masses in middle-aged male smokers. They are undifferentiated tumors composed of sheets of small/epithelioid and/or rhabdoid tumor cells variably expressing epithelial markers and consistently showing loss of BRG1 and the closely related protein, Brahma (BRM). Frequent expression of stem cell markers (SOX2, CD34, SALL4) is noted. Despite gene expression profiles similar to MRTs and SCCOHT, they show striking genomic overlap with SMARCA4-mutant NSCLC with frequent TP53, STK11, KEAP1, and KRAS mutations, high tumor mutation burden (TMB), and presence of smoking related molecular signatures in tumor cells. SMARCA4-UT show uniformly poor survival and are irresponsive to conventional therapies. Immunotherapy responses are variable but promising, although PDL1 expression appears to be of poor predictive value. Drugs exploiting genetic and epigenetic mechanisms of SMARCA4 antagonism hold promise for future targeted therapies.