Pathologic features of head and neck adult rhabdomyosarcoma: Case series.

INTRODUCTION: Adult Head and neck Rhabdomyosarcomas (HNRMS) are exceedingly rare and remain challenging for pathologists. CASES PRESENTATION: Five cases of adult HNRMS (≥19 years) were retrieved from the archives of the Department of Pathology of Hospital of Specialities in Rabat (HSR) in Morocco, over 5 years. Clinical and pathologic findings from hematoxylin and eosin slides and immunohistochemistry for Desmin and Myogenin were reviewed. CLINICAL DISCUSSION: The median age was 33, with a men's predominance (3 M/2F). Histological analysis revealed three cases of Alveolar Rhabdomyosarcoma (RMS), one Pleomorphic RMS, and one spindle cell/sclerosing RMS. In addition to the typical histology observed in each RMS, we found tricky growth patterns that could be a source of misdiagnosis. All five cases demonstrated variable positivity for Desmin and Myogenin. CONCLUSION: HNRMS cases have different pathological features than pediatric RMS cases. We identified rare subtypes such as pleomorphic and spindle cell/sclerotic RMS, which exhibit unusual morphological patterns.

Primary epithelioid angiosarcoma of the mandibular gingiva: diagnostic pitfalls, about an unusual entity.

Primary angiosarcoma of the oral cavity is a rare malignant vascular neoplasm variably recapitulating endothelial cells and is generally associated with a worse prognosis. The epithelioid subtype is even uncommon in this localization. To our knowledge, only seven cases of primary oral epithelioid angiosarcoma have been reported until 2021. This histopathological variant is characterized by solid and sheet-like growth patterns that may be misinterpreted as other lesions with epithelioid cells. Herein, we present a new case of primary epithelioid angiosarcoma of the mandibular gingiva to discuss histopathological differential diagnoses and potential diagnostic pitfalls.

Pseudomyogenic Hemangioendothelioma Arising in the Maxillary Sinus, an Uncommon and Misdiagnosed Tumor: A Case Report.

Pseudomyogenic hemangioendothelioma (PMHE) is a rare vascular neoplasm with an intermediate to low-grade malignant potential. Only 5% of PMHEs occur in the head and neck. This tumor exhibits different histological patterns and mimics other vascular tumors, myoid tumors, or carcinomas. The distinction between these tumors can be a very challenging situation for pathologists. In this article, we report the first case, to our knowledge, of PMHE arising in the maxillary sinus, to highlight this uncommon entity and discuss differential diagnoses.