Overt Gastrointestinal Bleed due to an Occult Cause: Mesocolic Hydatid Cyst with Sinistral Portal Hypertension

A BSTRACT Hydatid disease, caused by Echinococcus granulosus , is endemic in many parts of the world, including the Indian subcontinent. It most commonly affects the liver (60%–70%) and lungs (20%–30%), while other sites are rare but increasingly reported. Primary peritoneal, splenic, and mesocolic hydatid cysts account for fewer than 2% of all cases and often pose diagnostic dilemmas. These cysts may present with nonspecific symptoms, mass effect, or complications such as rupture. Upper gastrointestinal hemorrhage due to sinistral portal hypertension caused by a hydatid cyst is exceedingly rare. We report a 17-year-old boy who presented with recurrent episodes of hematemesis and melena for 2 months, associated with progressive fatigue, anemia, and thrombocytopenia. Endoscopy revealed actively bleeding isolated fundal varices, managed with glue injection. Cross-sectional imaging showed a cystic lesion with peripheral calcification in the lesser sac, splenomegaly, and multiple venous collaterals. Intraoperatively, the lesion was found in the transverse mesocolon, compressing the tributaries to the splenic vein. The cyst was excised after evacuation and scolicidal instillation, and splenectomy was performed. Histopathology confirmed hydatid disease. The patient had an uneventful postoperative recovery. Mesocolic hydatid cysts are extremely rare and can present with unusual, potentially life-threatening complications such as variceal bleeding from sinistral portal hypertension. This case highlights the importance of considering hydatid disease in the differential diagnosis of unexplained variceal bleeding in endemic areas, even in the absence of liver involvement.