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* 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 provided 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. (Arch Pathol Lab Med. 2022;146:1122-1130; doi: 10.5858/arpa.2021-0001-OA), The sinonasal tract harbors a diverse spectrum of high-grade neoplasms, many of which have considerable overlapping morphologic features owing to their poorly differentiated or undifferentiated appearance. (1,2) Some of these [...]

Introduction: Pediatric orbital tumors encompass a wide spectrum of neoplasms, many of which are malignant small round cell tumors with overlapping histology. Sarcomas with BCOR genetic alterations are undifferentiated round cell sarcomas (URCS) characterized by BCOR rearrangements or internal tandem duplications, having distinct clinical features. Being previously unrecognized in the orbit, they have potential for misdiagnosis. Patients: We describe two cases of orbital sarcomas with BCOR genetic alterations. Results: Both girls, 8 and 16 months of age, respectively, presented with progressive proptosis. Both tumors showed sheets of round to ovoid cells with monomorphic nuclei and frequent mitoses. Delicate branching capillaries and myxoid stroma were absent. Diffuse BCOR, cyclin D1, and SATB2 immunopositivity was present. Conclusion: Orbital sarcomas with BCOR genetic alterations are extremely rare. Pathologists should have high index of suspicion for novel genetically defined entities in the differential diagnosis of pediatric orbital URCS and perform appropriate ancillary tests for accurate diagnosis. [ABSTRACT FROM AUTHOR]

Ameloblastic carcinoma (AC) is an aggressive odontogenic tumor. Spindle cell variant of AC (SCAC) is a rare entity and only sixteen cases of SCACs have been reported in the literature till date. We reported a case of 42-years-old male presented with swelling in right lower posterior region for 3 years. Radiology revealed multilocular osteolytic with cortical thinning and rarefaction showing internal non-enhancing areas. Histologically, the tumor revealed areas characteristic of ameloblastoma along with hypercellular areas of monomorphic spindle shaped cells merging into the stroma displaying cytological atypia, suggestive of AC with spindle cell variant. The purpose of this case report is to document an unusual case of spindle cell variant of AC, which can mimic other oral spindle cell lesions. Additionally, proliferative marker along with histological parameters like cytological atypia, mitoses and cell morphology is emphasized. [ABSTRACT FROM AUTHOR]

Background: Pre‐vascular facial nodes (PV‐FNs; perifacial lymph nodes) are supra‐mandibular lymph nodes above the inferior border of the mandible. These are not part of routine neck dissection done for OCSCC. These lymph nodes can be sentinel station for metastatic lymph nodes from gingivobuccal complex cancers and are missed during routine neck dissection. It is imperative to include this sentinel station in routine neck dissection to prevent nodal recurrences. Materials and Methods: One hundred thirty‐seven patients with GBCC (T1–T4) were prospectively recruited between May 2020 and June 2022 with the intent to evaluate the incidence of PV‐FN metastases and clinicopathological factors predicting them. Results: PV‐FN metastases were seen in 26 patients (18.9%; 26/137). The occult metastasis rate was 8.7% (12/137). On multivariate analysis, pathological T4 stage (pT4), LVE positivity, and intermediate‐high BGS were statistically significant predictors of PV‐FN metastases in our study. Conclusions: Incidence of PV‐FN metastasis is high (18.9%) in GBCC, which can be potentially the first sentinel station in the lymphatic drainage pattern for this sub‐site. Meticulous clearance of this nodal basin is of paramount importance during neck dissection to prevent nodal recurrences. Level of Evidence: 2 (CEBM‐Level of Evidence‐2.1) Laryngoscope, 135:148–152, 2025 [ABSTRACT FROM AUTHOR]