Iliopsoas hydatid cyst mimicking an ovarian tumor: a diagnostic pitfall in an endemic setting—a case report

BACKGROUND: Cystic echinococcosis is endemic in Ethiopia. Although the liver and lungs are most commonly affected, primary involvement of the iliopsoas muscle is rare and may closely mimic gynecologic pathologies, leading to diagnostic delay or mismanagement. CASE PRESENTATION: We report the case of an 18-year-old Ethiopian woman who presented with a two-year history of progressively worsening lower abdominal pain and a palpable right lower abdominal mass. Initial ultrasonography suggested a right adnexal cystic lesion. Subsequent computed tomography demonstrated a well-defined cystic mass adjacent to the right iliopsoas muscle. Surgical exploration through a right lower abdominal oblique (Modified Rutherford-Morrison) incision revealed a 10 × 8 cm hydatid cyst arising from the iliopsoas muscle; the dimensions were confirmed intraoperatively. The cyst contained a dominant daughter cyst and multiple smaller daughter cysts. Histopathological examination confirmed cystic echinococcosis. The patient underwent complete pericystectomy followed by albendazole therapy, with uneventful postoperative recovery. CONCLUSION: This case highlights the diagnostic challenge posed by hydatid disease in unusual anatomical locations, where it can closely mimic gynecologic or neoplastic pathologies. In endemic settings, timely diagnosis requires heightened clinical suspicion and appropriate imaging, while optimal outcomes depend on coordinated multidisciplinary management integrating definitive surgery and antiparasitic therapy.