Primary Hydatid Cyst of the Tongue: A Rare Clinical Case Report

Hydatid disease (echinococcosis) is a parasitic infection caused by the larval stage of Echinococcus granulosus. Although the liver and lungs are the most commonly affected organs, involvement of the head and neck region is exceedingly rare. Localization within the oral cavity, particularly the tongue, is exceptionally uncommon due to its constant mobility, rich vascularity, and lack of lymphatic stasis. We report a case of a 31-year-old Syrian female who presented with a gradually progressive, painless swelling of the tongue. Magnetic resonance imaging (MRI) revealed a 2.0 × 2.0 cm cystic lesion involving the left genioglossus muscle, exhibiting a detached internal membrane and a “daughter cysts” sign findings highly suggestive of a hydatid cyst. Fine needle aspiration produced clear fluid, followed by surgical excision of the lesion under local anesthesia. Histopathological examination demonstrated a thin, lamellated, eosinophilic cyst wall with lymphocytic and eosinophilic infiltration, confirming the diagnosis of a hydatid cyst. Hydatid cysts of the tongue are extremely rare, with fewer than ten cases reported worldwide. The clinical presentation often mimics benign cystic lesions such as mucoceles or dermoid cysts, making diagnosis challenging. MRI findings and histopathological confirmation are essential for accurate identification. Complete surgical excision remains the treatment of choice, with care taken to prevent cyst rupture and secondary dissemination. This case represents a rare instance of a primary hydatid cyst of the tongue in a Syrian patient operated in Libya. It underscores the importance of considering hydatid disease in the differential diagnosis of cystic lesions of the oral cavity, especially in patients from endemic regions or with a history of animal exposure. Early diagnosis and meticulous surgical management ensure excellent outcomes.