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.