Case Report: An exceptional localisation in the thigh of a giant primary subcutaneous hydatid cyst. [version 1; peer review: awaiting peer review]

Hydatid disease is a zoonotic disease caused by the larval stage of Echinococcus granulosus and is found globally. Although the liver and lungs are the most prevalent sites of involvement, sub-cutaneous hydatid cysts are rare especially in the primary occurrence. Sub-cutaneous hydatid cysts usually are noticed as slow growing, painless, and mobile masses beneath the overlying skin which is usually normal and are generally found on the trunk and proximal extremities. To the best of our knowledge, very few cases of primary subcutaneous hydatid cysts of the thigh have been documented. We present a case of a 30-year-old woman from a rural setting, who has a large, painless swelling on her thigh. Imaging studies confirmed the presence of a primary subcutaneous hydatid cyst, which is an atypical presentation of the disease. The entire lesion was excised surgically without any evidence of recurrence for a long period postoperatively. This case illustrates the difficulty in establishing a diagnosis and the importance of early surgical management in these cases.