[Clinicopathologic and molecular genetic characterizations of biphenotypic sinonasal sarcoma]

Integrated Molecular and Histological Insights for Targeted Therapies in Mesenchymal Sinonasal Tract Tumors

PURPOSE OF REVIEW

This review aims to provide a comprehensive overview of mesenchymal sinonasal tract tumors (STTs), a distinct subset of STTs. Despite their rarity, mesenchymal STTs represent a unique clinical challenge, characterized by their rarity, often slow progression, and frequently subtle or overlooked symptoms. The complex anatomy of the sinonasal area, which includes critical structures such as the orbit, brain, and cranial nerves, further complicates surgical treatment options. This underscores an urgent need for more advanced and specialized therapeutic approaches.

RECENT FINDINGS

Advancements in molecular diagnostics, particularly in next-generation sequencing, have significantly enhanced our understanding of STTs. Consequently, the World Health Organization has updated its tumor classification to better reflect the distinct histological and molecular profiles of these tumors, as well as to categorize mesenchymal STTs with greater accuracy. The growing understanding of the molecular characteristics of mesenchymal STTs opens new possibilities for targeted therapeutic interventions, marking a significant shift in treatment paradigms. This review article concentrates on mesenchymal STTs, specifically addressing sinonasal tract angiofibroma, sinonasal glomangiopericytoma, biphenotypic sinonasal sarcoma, and skull base chordoma. These entities are marked by unique histopathological and molecular features, which challenge conventional treatment approaches and simultaneously open avenues for novel targeted therapies. Our discussion is geared towards delineating the molecular underpinnings of mesenchymal STTs, with the objective of enhancing therapeutic strategies and addressing the existing shortcomings in the management of these intricate tumors.

Biphenotypic Sinonasal Sarcoma with Orbital and Skull Base Involvement Report of 3 Cases and Systematic Review of the Literature

Biphenotypic sinonasal sarcoma (BSNS) is a rare malignant tumour of the upper nasal cavity and ethmoid sinuses that presents predominantly in middle aged female patients and show a characteristic infiltrative and hypercellular proliferation of spindle cells that demonstrate a specific immunoreactivity. We present three cases with BSNS that had different presenting complaints, either sinonasal or orbital problems, underwent endoscopic surgical treatment and/or radiotherapy and have been disease free on long follow up. A systematic review of all published cases was performed to identify all BSNS cases known at present. BSNS requires prompt and correct diagnosis with accurate surgical resection as well as consideration of radiotherapy. Our three cases confirm the findings of the literature and support that BSNS is an aggressive but treatable malignant disease of the sinonasal tract.

Biphenotypic sinonasal sarcoma: Report of 3 cases with a review of literature

Biphenotypic sinonasal sarcoma (BSNS) is a rare recently described distinct spindle cell sarcoma which arises exclusively in the sinonasal region and is characterized by concomitant neural and myogenic differentiation. Before this neoplasm was characterized, most were classified as other entities including adult fibrosarcoma, monophasic synovial sarcoma and malignant peripheral nerve sheath tumor. By immunohistochemistry, these tumors characteristically express S100 and smooth muscle actin (SMA) and/or muscle specific actin (MSA). Most cases harbor rearrangements of PAX3 (paired box gene 3), and the most frequent translocation partner is MAML3 (mastermind like transcriptional coactivator 3). Herein, we described three cases of BSNS involving the nasal cavity with or without paranasal sinus involvement. We also did a literature review of the clinical features, histologic and immunophenotypic findings, cytogenetics, pathogenesis and behavior of this rare entity.

Biphenotypic sinonasal sarcoma: demographics, clinicopathological characteristics, molecular features, and prognosis of a recently described entity

Biphenotypic sinonasal sarcoma (BSNS) is a recently recognized type of sarcoma arising exclusively in the sinonasal tract displaying unique clinical course, histopathology, and genetics. Due to its rarity, only case series and case reports are available. In order to provide an overview of the current understanding of this disease, we present a comprehensive review of the literature and present three previously unreported cases of BSNS. A total of 55 genetically characterized and 41 cases without molecular data were identified in the literature. Two-thirds of patients were female and the peak incidence was in the fifth decade. Fatal outcome was rare (two cases with intracranial extension) and local recurrence occurred in 31.6%, all occurring within 5 years after initial treatment. Histologically, BSNS is highly cellular in the majority of cases and composed of fascicles of spindle cells, with entrapped hyperplastic surface epithelium being a frequent finding. The immunohistochemical profile is characteristic due to the biphasic nature of this lesion, with shared features of both myogenic and neural origin. Rhabdomyoblastic differentiation is apparent in a subset of cases. The most common genetic event is the PAX3-MAML3 fusion (58.6%) but isolated PAX3 rearrangement (19.2%), absence of rearrangements (9.1%), PAX3-FOXO1 (8.1%), PAX3-NCOA1 (4%), and isolated MAML3 rearrangement (2%) have also been reported. In conclusion, the recognition of BSNS is crucial due to its relatively indolent clinical course. A selected immunohistochemical panel and/or molecular confirmation can be used to aid in appropriate diagnosis and consequently in prognostication and to avoid overtreatment with chemotherapy regimens used in its mimics.