RESUMO
INTRODUCTION AND IMPORTANCE: The tapeworm Echinococcus granulosus sensu lato is the causative agent of cystic echinococcosis (CE), often known as hydatid disease. Over two-thirds of all occurrences of this zoonotic disease process in humans are caused by hepatic infection. Clinicians should have a low threshold to consider CE as a differential diagnosis in patients with positive serology and suggestive radiological findings, especially in endemic regions, because signs and symptoms are typically non-specific, especially in early disease. CASE PRESENTATION: This is a case report of a 26-year-old male who presented with increasing lower abdominal discomfort, mild pain, sense of fullness in the lower abdomen, described as (I'm having a ball in my abdomen), with a history of early satiation and tenesmus, frequency of urine, and history of weight loss and general weakness of 10-months duration. The diagnosis of a hydatid cyst in the mesorectum was made. The cyst was completely excised via open surgery. No local recurrence has been detected up to the present time. CLINICAL DISCUSSION: Given how uncommon a site like this is, this case report helps broaden the differential diagnosis of soft tissue masses in such settings, especially in endemic areas. It also describes in great detail how these locations are affected by the hydatid disease. CONCLUSION: The mesorectal hydatid cyst was challenging to diagnose initially due to its infrequent incidence and uncommon location. In a few rare cases, the diagnosis of a hydatid cyst might be guided by the detection of the cyst membrane and daughter cysts in the germinal membrane.