[Hydatidosis of psoas muscle revealed by vascular axis compression in lower limb: About one case at the Ibn Sina University hospital, Rabat, Morocco]. / Hydatidose du muscle psoas révélée par une compression de l'axe vasculaire du membre inférieur : À propos d'un cas au Centre hospitalier universitaire Ibn Sina, Rabat, Maroc.

Introduction: Hydatidosis is a zoonosis caused by Echinococcus granulosus. It's a real public health problem in Morocco. Muscle localization is unusual, even in endemic countries. We report a rarely described case of a hydatid cyst of the psoas muscle diagnosed in our laboratory. Case report: The patient was a 32-year-old male, living in a rural area. He reported a contact with dogs. He was admitted in vascular surgery department for left hypochondrium pain, with heaviness of the left lower limb and appearance of varicose veins. Clinical examination has found a huge painful and hard mass of the left flank arriving to the hypogastrium with varicose veins of the left leg. An injected CT scan of the pelvic region showed a 189 x 137 mm cystic mass of the left psoas muscle reflowing left iliac vessels. This suggested hydatid cyst. No other localization was found. Hydatid serology was positive with an ELISA test and an indirect hemagglutination test. The patient underwent surgery to remove the mass. Several white vesicles of a few centimeters were found in the cyst and were sent to the parasitology laboratory. Microscopic examination has confirmed the presence of viable Echinococcus granulosus. The patient received albendazole 400 mg twice daily for only a month and was not seen for follow-up. One year after surgery, he showed the same symptoms of abdominal pain and heaviness. Recurrence of hydatid cysts in the same localization was diagnosed with ultrasound showing two hydatid cysts type 3 according to Gharbi classification. Discussion: Diagnosis of all hydatidosis localizations is based on epidemiological, clinical, and radiological data and confirmed by serology and parasitological examination of the surgical specimen. Surgery is then a diagnostic and therapeutic tool that cannot be bypassed since it allows the definitive elimination of the parasite and eviction of recurrence if it's well done. Conservative methods are related to recurrent cysts. Conclusion: Muscle hydatidosis is extremely rare but should not be forgotten when radiological and epidemiological data suggest it. It's a benign infection but can be severe and deadly if not appropriately treated.