[Primary hydatid cyst of the psoas muscle: description of 9 cases in Tunisia and review of the literature].

The psoas muscle is an uncommon location for hydatid cyst accounting for only 1 to 3% of cases. The purpose of this report is to describe the epidemiologic, clinical, paraclinical, and therapeutic features of primary hydatid cyst of the psoas muscle. A retrospective study conducted in Surgery Department A at the Rabta Hospital in Tunisia compiled a total of 9 cases of primary hydatid cyst of the psoas muscle treated between 1980 and 2006. There were 6 men and 3 women with a mean age of 42.8 years. Symptomatology was nonspecific with pain in 6 cases. Discovery was coincidental in two cases. Clinical examination detected a mass in the presents of an abdominal mass in 7 cases. Radiologic findings (ultrasound and/or CT scan) confirmed diagnosis in 8 cases. In one case a mistaken diagnosis of psoas muscle abscess was made in a patient with an infected hydatid cyst. Serological tests were performed in 4 cases and were positive in 3. All patients underwent surgical treatment. The extraperitoneal approach (Leriche) was used in 7 cases and the transperitoneal approach via median laparotomy in 2. In all cases the surgical procedure consisted of partial cystectomy leaving a part of the pericystic against neurovascular structures. There was no operative mortality. The only postoperative complication was urinary infection in one patient. Mean follow-up was 2.5 years. One local recurrence was observed 4 years after surgical treatment and required reoperation.