Hepatic Alveolar Echinococcosis Mimicking Perihilar Cholangiocarcinoma: A Case Report.

Background: Hepatic alveolar echinococcosis (HAE), although rare, is a potentially life-threatening parasitic disease when left untreated. Following infection, the disease typically progresses through a prolonged asymptomatic latent phase, resulting in delayed clinical presentation in most patients. The radiological appearance of HAE may closely resemble that of primary hepatic malignancies, thereby creating significant diagnostic challenges. Case Presentation: We report the case of a 49-year-old previously healthy man who presented with cholestatic liver enzyme abnormalities and imaging findings suggestive of biliary obstruction. Cross-sectional imaging revealed a calcified hilar hepatic mass with biliary dilatation and multiple heterogeneous liver lesions, strongly suggestive of perihilar cholangiocarcinoma. Endoscopic retrograde cholangiopancreatography (ERCP) with brush cytology was initially negative for malignancy. Subsequent magnetic resonance imaging (MRI) demonstrated an infiltrative multiloculated solid-cystic hepatic lesion involving the right hepatic lobe and hilar structures. Definitive diagnosis was ultimately established through liver biopsy and positive serology for alveolar echinococcosis. The patient was treated with albendazole followed by extended right hepatectomy, with favorable postoperative recovery. Conclusion: HAE may closely mimic perihilar cholangiocarcinoma, exhibiting similar clinical and radiological characteristics. Maintaining a high index of suspicion and obtaining adequate tissue biopsies are essential for establishing an accurate diagnosis and ensuring timely, appropriate management.