Diaphragmatic Hydatidosis: A Rare Location, A Case Report

Abstract: Hydatid disease, a parasitic infection caused by “Echinococcus granulosus”, most commonly affects the liver and lungs. Primary involvement of the diaphragm is an exceedingly rare presentation, accounting for approximately 1% of cases, and poses a significant diagnostic challenge as it can mimic cysts originating from the hepatic dome or the lung base. This article synthesizes the crucial role of medical imaging in the diagnosis, characterization, and management of diaphragmatic hydatidosis. While chest radiography and ultrasound (US) may provide initial clues, cross-sectional imaging with computed tomography (CT) and magnetic resonance imaging (MRI) is paramount for a definitive diagnosis and pre-operative planning. We detail the specific imaging findings across these modalities, including the Gharbi classification on US and signs of complications on CT. Emphasis is placed on the key radiological signs for precise topographic localization, such as the “claw sign,” the visualization of a thinned and stretched diaphragmatic muscle around the lesion, and the superior soft-tissue delineation on T2-weighted MRI sequences. A thorough understanding of these imaging features is essential for radiologists to accurately diagnose this rare entity, particularly in endemic regions. We report the case of a 67-year-old incarcerated patient admitted with chronic dyspnea of recent worsening, associated with chest pain, right hypochondrial heaviness, and distension, An initial ultrasound suggested a hydatid cyst of the hepatic dome. Computed tomography revealed a large inter-hepato-diaphragmatic hydatid cyst, very likely of diaphragmatic origin. The diagnosis was subsequently confirmed at surgery.