Rhabdomyosarcome embryonnaire du plancher buccal

Embryonic rhabdomyosarcoma (RMS) of the buccal floor muscle is exceptional in adults. RMS represents 3% of soft tissue sarcomas in adults and mainly affects children, accounting for 8% of solid tumors in children. RMS develops from the embryonic mesenchymal cell throughout the body, exceptionally in the floor of the mouth. Its pathogenesis is unclear but may be associated with congenital syndromes. The global classification distinguishes alveolar RMS, with poor prognosis, embryonic RMS, with good prognosis, and intermediate forms. We report a rare case of RMS involving the muscles of the floor of mouth in a 40-year-old woman. PET, CT and MRI provided the diagnosis of poorly differentiated embryonal RMS that was confirmed by immunohistochemistry after ruling out the alveolar subtype by cytogenetic and molecular biology analysis. Radical surgical resection followed by chemotherapy and radiotherapy resulted in complete remission. We discuss the clinical, radiological, immunohistochemical, genetic and molecular aspects of RMS with a review of the literature.