Intramuscular hydatid cyst of paraspinal muscle: A diagnostic challenge.

Hydatid cyst is a zoonosis caused by ingestion of eggs of Echinococcus-a tapeworm. Following ingestion of the eggs, oncosphere larvae are released which penetrate the intestinal wall to invade various organs of the body including liver, lungs, and skeletal muscles via. blood vessels. Due to their contractile nature and high lactic acid content, skeletal muscles are typically not a suitable site for attachment of hydatid cyst. In our case report presented below, we report a rare case of an isolated hydatid cyst of paraspinal muscle presenting as a slow-growing asymptomatic mass in the back, posing a clinical diagnostic dilemma.