Primary hydatid cyst of the thigh.

Echinococcosis of the musculoskeletal system is found in 0,5-4% of the patients suffering from hydatid disease. We describe a case of primary hydatid cyst of the posterior thigh in a 73 year-old woman, who presented with a painless mass. The diagnosis was set intraoperatively after biopsy of the cyst wall. A wide excision of the cyst with part of the attached muscles was performed. The postoperative course of the patient was uneventful. A postoperative CT-scan of the thorax and abdomen revealed no signs of other echinococcal cysts. Thus, the case was considered as a primary hydatid cyst of the thigh. The patient received adjuvant oral treatment with albendazole for six months. The patient remains in good general condition and without any signs of recurrence, one year after the operation. Hydatid disease should be considered in the differential diagnosis of any cystic mass detected in the thigh, especially if occurs in regions where the disease in endemic.