SMARCB1 (INI1)-deficient sinonasal carcinoma manifesting as oral lesions: A report of two cases.

BACKGROUND: Sinonasal carcinomas represent a rare group of malignancies, accounting for less than 5% of all head and neck cancers and a worldwide incidence of less than 1 case per 100 000 inhabitants annually. Despite the restricted anatomical location, sinonasal carcinomas harbor some of the most histologically and molecularly diverse groups of tumors. SMARCB1 (INI1)-deficient sinonasal carcinomas are locally aggressive tumors commonly detected late, leading to devastating morbidity and mortality. CASE REPORT: We present two cases of SMARCB1-deficient sinonasal carcinoma involving the oral cavity and presenting as progressive radiolucent lesions with local swelling associated with maxillary dentition and alveolar bone. Both cases were initially considered odontogenic in origin and involved the destruction of the left anterior maxilla. CONCLUSION: Given the rarity and the variable presentation of these tumors, they pose a challenge for head and neck surgeons, dentists, and pathologists due to the potential overlapping features with odontogenic and non-odontogenic inflammatory and neoplastic lesions. These cases highlight the importance of a multidisciplinary team and include SMARCB1-deficient sinonasal carcinomas in the differential diagnosis of destructive lesions of the maxilla.

A 10-Year Review of Intraoral Salivary Gland Tumor Diagnoses: Diagnostic Challenges and Inter-Observer Agreement.

BACKGROUND: Salivary gland tumors (SGT) are a diverse group of neoplasms arising from the major and minor glands. The oral cavity is the most common site for minor SGT (IMSGT), and these lesions frequently pose a challenge to the pathologist due to overlapping histopathological features and limited material for analysis. Our objective was to determine specific clinical and histopathological features associated with challenges in IMSGT diagnoses and pathologists' agreement. METHODS: We conducted a retrospective analysis of 248 IMSGT received between 2010 and 2019. We evaluated the diagnostic challenge of the cases by stratifying according to whether a definitive, favored, or indeterminate (challenging) diagnosis was provided. Inter-observer agreement and concordance of biopsy diagnoses with the final diagnoses after tumor resection were evaluated. RESULTS: Of the 248 biopsies, 191 had a definitive diagnosis, 38 favored diagnoses, and 19 were indeterminate. The predominant diagnoses considered for the indeterminate category were pleomorphic adenoma/myoepithelioma (PA), polymorphous adenocarcinoma (PAC), adenoid cystic carcinoma (AdCC), and low-grade adenocarcinoma. Using multivariate analysis of clinical features, younger patient age, smaller tumor size, and larger biopsy size increased the likelihood of a definitive diagnosis (p = 0.014, p = 0.037, p = 0.012). The inter-observer agreement for 68 representative cases was moderate overall (Fleiss's Kappa 0.575) and good for the 40 cases with a definitive diagnosis (Fleiss's Kappa 0.66). Sixty-five biopsy diagnoses were matched with corresponding tumor resection diagnoses and found to show a good concordance (Cramer's V test 0.76). The discordant diagnoses predominantly involved PA, carcinoma exPA, PAC, AdCC, and adenocarcinoma NOS. CONCLUSION: Diagnostic challenges in IMSGT incisional biopsies were infrequent, especially if multiple pathologists were consulted. PA, PAC, AdCC, and adenocarcinoma NOS were the histologic types more commonly posing diagnostic challenges. Younger patient age, smaller tumor size, and larger biopsy are associated with a definitive diagnosis. This data highlights the importance of appropriate sampling in IMSGT.