Primary parotid intraductal rhinosporidiosis: A rare extranasal presentation

Rhinosporidiosis is a chronic granulomatous infection caused by Rhinosporidium seeberi , an aquatic protistan parasite of the class Mesomycetozoea. While the nasal cavity and nasopharynx are the most common sites of involvement, primary infection of the parotid (Stensen’s) duct is exceedingly rare. Parotid duct rhinosporidiosis often mimics benign cystic or vascular lesions pre-operatively, and definitive diagnosis depends on histopathological identification of characteristic sporangia. We report the case of a 53-year-old male from an endemic region who presented with a 2-month history of gradually progressive left facial swelling associated with blood-tinged intraoral discharge. Ultrasonography revealed a hypoechoic vascular mass along the parotid duct, and fine-needle aspiration cytology suggested a suppurative lesion. The patient underwent left total parotidectomy with simultaneous transoral excision of the intraductal mass. Histopathological examination of the excised specimen revealed a cystically dilated duct lined by stratified squamous epithelium with reactive atypia and numerous sporangia containing sporangiospores, confirming the diagnosis of primary intraductal rhinosporidiosis. This case highlights the diagnostic challenges posed by extranasal rhinosporidiosis, which can simulate neoplastic or vascular lesions clinically and radiologically. Histopathology remains the gold standard for diagnosis. Surgical excision with clear margins is curative, and the patient remained disease-free at 6-month follow-up. Rhinosporidiosis of the parotid duct should be considered in the differential diagnosis of atypical parotid swellings, particularly in patients from endemic regions. Awareness of this rare entity is essential to avoid misdiagnosis and to guide appropriate surgical management.