[Primary giant hydatid cyst in the thigh].

Human hydatid cyst is a zoonotic infection that usually attacks visceral organs. Primary soft tissue involvement is very rare, causing a diagnostic challenge. Primary soft tissue hydatid cyst was encountered in an 83-year-old man, which presented as a giant lesion in the posterior aspect of the right thigh, extending from the gluteal region proximally to the popliteal region distally. A multiloculated cystic mass was completely resected and histopathological examination confirmed the preoperative diagnosis. No local or systemic complications occurred postoperatively. The patient recovered fully at the end of postoperative 12 months.