Lesions located at the liver periphery: A stepwise cross-sectional imaging approach toward diagnosis

Lesions at the liver periphery may originate from intrahepatic or extrahepatic tissues due to the unique anatomical, peritoneal, and hemodynamic characteristics of the hepatic capsular and subcapsular regions. In this article, the anatomical and physiological factors predisposing the hepatic periphery to pathology are examined, including Laennec's capsule, perihepatic ligamentous connections, and alternative blood supply pathways. A stepwise imaging approach is outlined, emphasizing the role of computed tomography (CT) and magnetic resonance imaging (MRI) in lesion differentiation based on key imaging features. Intrahepatic lesions discussed include focal confluent fibrosis, ciliated foregut cyst, perihepatic abscess, inflammatory pseudotumor, epithelioid hemangioendothelioma, and intrahepatic cholangiocarcinoma. Extrahepatic causes of capsular involvement, such as diaphragmatic slips, pseudolipoma of Glisson's capsule, splenosis, hepatic tuberculosis, Fitz-Hugh-Curtis syndrome, hepatic endometriosis, peritoneal metastases, peritoneal carcinomatosis, pseudomyxoma peritonei, and peritoneal mesothelioma are also reviewed. Most benign lesions can confidently be diagnosed with either CT or MRI and without further intervention, though hepatic inflammatory pseudotumors may require biopsy. Most malignant lesions need pathological confirmation and treatment strategy. Effective management of focal liver lesions involves a multidisciplinary team, including radiologists, hepatologists, and surgeons, ensuring a comprehensive and individualized approach to patient care. On these bases, this review aims to provide a comprehensive review of benign and malignant focal liver lesions with a predilection for the hepatic periphery, including traumatic, infectious, inflammatory, and neoplastic conditions.