Giant Hydatid Cyst Originating from Psoas Muscle Extending to the Iliac Bone, Inguinal, and Femoral Canals: A Case Report and Current Literature Review

Retroperitoneal hydatid cysts are extremely rare and difficult to distinguish from other intra-abdominal pathologies, such as synovial sarcoma. In this study, we present a rare case of a complicated retroperitoneal hydatid cyst originating from the psoas muscle without any other focus. A 59-year-old male patient presented to the outpatient clinic with complaints of constipation and a feeling of gradually increasing swelling in the left lower quadrant of the abdomen and left groin area, progressing toward the left leg. In the examinations performed, a multiloculated giant hydatid cyst that filled the left pelvis in the retroperitoneal region, deviated the intra-abdominal organs to the right side, and extended to the left femoral and inguinal canals was detected. The patient underwent surgical excision and was followed up during the postoperative period. No evidence of recurrence was found at the patient's 3rd and 6th month followups. Primary muscle hydatid cysts necessitate a distinct approach to treatment and management when compared with hydatid cysts in other bodily organs. While recurrences remain a potential concern after resection, it is noteworthy that the window for the formation of fertile cysts typically spans up to 10 months. Thus, it is advisable to conduct regular postoperative follow-up examinations during the first year following surgery to ensure comprehensive monitoring and care.