Intramuscular cystic echinococcosis is a very rare occurrence. Herein we report a case of a 37-year-old patient who presented with progressive swelling of his left thigh. Ultrasound evaluation showed a multicystic, encapsulated lesion (16 × 3.5 × 8.5 cm) in the M. vastus lateralis, and serology confirmed the diagnosis of Echinococcus granulosus s.l. infection. No additional cysts were detected upon total body CT scan. The patient was treated with albendazole pre-operatively; surgical resection of the mass was then successfully performed. The patient feels well and no signs of residual infestation were seen after 2 years of follow-up.
Keywords: Case report; Echinococcus granulosus; Muscular echinococcosis; Thigh.