Unexpected Site of Hydatid Cyst, in Thigh- A Case Report

Introduction: Hydatid cyst is a parasitic disease common in India. Usual locations of the cyst are the lungs and liver. The occurrence of the hydatid cyst in other locations is rare.

Presentation: The presenting concern is a 10-year-old girl with a painless swelling in lower 1/3rd of the right thigh on the posterior side. Clinical examination is suggestive of a palpable cystic swelling which is involving the muscle underlying it. USG and CT of thigh revealed a cystic swelling in the Biceps femoris muscle with high suspicion of hydatid cyst. Pre-operative albendazole was used followed by complete removal of the cyst and the use of albendazole postoperatively.

Discussion: Hydatid cyst most commonly utilizes oxygen for growth, but skeletal muscle contains Lactic acid. Hence occurrence of cyst in skeletal muscle is rare. Ultrasound has a sensitivity of 100% in typical cases and is diagnostic. Computed tomography provides better information about cyst. Though chemotherapy is controversial, Preoperative and postoperative chemotherapy shown to decrease the incidence of recurrent disease. Excision in one piece with total cystectomy is the ideal process. Early treatment is mandatory to avoid local and general complications that are directly related to duration of cyst.

Conclusion: This case report helps us to keep hydatid cyst a differential diagnosis of intramuscular cystic swelling and treat accordingly. The presence of this cyst in unusual locations makes diagnosis and treatment challenging and more interesting. Timely diagnosis, timely intervention and chemotherapy is required to prevent intra operative complications and recurrence. This case study helps in making a specific management protocol and adds up to the previous case reports.