Primary Hydatid Cyst of the Skeletal Muscles: A Rare Presentation of Cystic Echinococcosis

Abstract

Hydatid cysts of the liver and/or lung are commonly seen in surgical practice in endemic areas like Iraq. Primary or secondary skeletal muscle hydatidosis is rarely reported, even in endemic areas. This is a case report of a 51 year-old, otherwise healthy, man with a firm non-fluctuant cystic swelling in the right thigh that was painless and growing slowly over a period of six months. While ultrasound and magnetic resonance imaging suggested a multilocular cystic lesion, other investigations failed to confirm the diagnosis of muscular hydatid cysts, especially in the absence of a primary cyst in the more common organs. The lesion was initially considered a soft tissue tumor but intraoperative exploration revealed a hydatid cyst with daughter cysts, that was excised and the patient was treated with Albendazole for 1 month postoperatively. The patient developed a seroma that disappeared spontaneously. There was no recurrence for up to 4 months of follow-up. This report illustrates that echinococcal disease should be considered in the differential diagnosis of a cystic mass in any anatomic location, especially when it occurs in endemic areas.