Infected primary hydatid cyst of the right lumbar paraspinal muscles: A rare case in a ten-year-old child

Most of the time, intramuscular hydatid cysts are secondary. The unusual topographies are a source of diagnostic delay and treatment difficulties. The aim of our case report is to put forward the features of this uncommon presentation and to propose a therapeutic management. We report the case of a primary hydatid cyst located in the right lumbar paraspinal muscles in a ten-year-old girl, in good health and without a pathological medical history. The patient presented with a discreet right lumbar swelling of firm consistency, painless and without signs of inflammation. Ultrasound and magnetic resonance imaging suggested the diagnosis of an intramuscular paravertebral hydatid cyst. The hydatid serology was positive. The patient had en-bloc resection of the cyst. He was infected with pus. The histopathological examination confirmed the diagnosis of muscular hydatidosis. Medical treatment was started. Three years after the operation, the MRI confirmed that was no recurrence. Echinococcus is a parasitic cestode that can infect dogs and other pets and farm animals, with humans as incidental hosts. Muscular hydatid localization, secondary to hematogenous dissemination, is rare, even in endemic countries. The combination of medical treatment with surgery ensures the best condition to avoid recurrence. In regions where hydatidosis is endemic, a tumor in any part of the body should be considered a hydatid cyst until proven otherwise. •In endemic areas, any swelling should suggest hydatid cyst.•A negative hydatid serology does not rule out the diagnosis of hydatid cyst.•The hydatid cyst infection can occur through the hematogenous route.•MRI is efficient for the diagnosis of infected hydatid cyst.•The infection can sterilize the hydatid muscle cyst.