Alveolar Sinonasal Rhabdomyosarcoma in Adults: A Case Report

Alveolar rhabdomyosarcoma is a malignant soft tissue tumor of myogenic origin that results from deregulation of protein production in skeletal muscle myogenesis. Rhabdomyosarcoma (RMS) is the most common malignant tumor of the nose and paranasal sinuses in pediatric populations; however, it is extremely rare in adults.

We present an interesting case of a 39-year-old woman with solid-type alveolar rhabdomyosarcoma (ARMS) in the right sinus cavity, eroding the skull base. After chemotherapy, surgical resection was performed followed by radiation. The definitive diagnosis of solid-type alveolar rhabdomyosarcoma was achieved after adequate CT-guided navigational biopsies and pathological evaluation supplemented by specific immunostains. The tumor was positive for Desmin (a general muscle marker) and Myogenin (a specific skeletal muscle marker), while negative for Cytokeratin (an epithelial marker).

Solid-type alveolar rhabdomyosarcoma is a rare neoplasm in the sinonasal tract of adults. Diagnosis and appropriate treatment requires PET/CT imaging, thorough pathologic evaluation aided by immunohistochemical testing, and aggressive management including chemotherapy followed by surgical resection and radiation.