Cytologic findings of an adult rhabdomyoma in the parapharyngeal space: A report of a case and review of the literature.

Adult extracardiac rhabdomyomas are rare benign mesenchymal tumor arising from skeletal muscle. While they are often located in the larynx and pharynx, the incidence in the parapharyngeal area is extremely rare with only 1 documented cytology case report to date. We report a case of an adult extracardiac rhabdomyoma in the parapharyngeal space diagnosed cytologically with subsequent histologic confirmation. The patient is a 57-year-old man with history of weight loss, hematuria, dysphagia, and airway encroachment. Computerized tomography of his abdomen showed a large left renal mass. While the patient was in the operating room for the resection of his renal mass, a fine-needle aspiration from left the parapharyngeal mass was performed. The smears showed uniform bland polygonal cells with abundant eosinophilic cytoplasm and peripherally located nuclei. Immunohistochemical stains performed on the cell block showed the tumor cells were desmin positive and negative for S-100 and PAX-8, supporting the diagnosis of an adult rhabdomyoma. Subsequent resection of the mass confirmed the diagnosis of an adult extracardiac rhabdomyoma.