Low grade includes PanIN-1 and PanIN-2  High grade includes PanIN-3 and carcinoma in situ • Low grade: Mild to moderate nuclear atypia • High grade: Marked nuclear atypia, loss of polarity, cribriforming,…

 Historically, these lesions have poorly defined histologic criteria and have been referred to by variety of names (e.g., fibroinflammatory polyp, fibroepithelial polyp, mucosal hyperplasia) Etiology/Pathogenesis • Probable result of mucosal injury…

 Some affected mothers and infants have inherited long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency  Carnitine palmitoyltransferase I deficiency also associated with fatty liver of pregnancy Clinical Issues • Most commonly occurs in last…

 Probably not distinct entity, but rather descriptive designation with associated clinical correlates Etiology/Pathogenesis • Majority of cases have no known cause or disease association • Some associated with hypersensitivity reactions, parasitic infection,…

 Often submitted for frozen section to rule out metastasis Microscopic • Uniformly sized tubules and acini with rounded outlines • Single layer of cuboidal to columnar cells that lack atypia, hyperchromasia, mitoses…

 Results in hepatosplenomegaly and pancytopenia • Variable disease progression • Enzyme replacement therapy represents mainstay therapy  Early diagnosis is crucial to improving outcome Microscopic • Accumulation of glucocerebroside in Kupffer cells and portal…

 Autosomal recessive Classification • Types A and B characterized by acid sphingomyelinase deficiency • Types C and D harbor cholesterol metabolism defect Etiology/Pathogenesis • Inherited lysosomal hydrolase deficiency leads to accumulation of sphingolipid…

 Typically 1-3 mm • No fibrous septa between nodules  But focal sinusoidal or periportal fibrosis can be seen • Inflammation is absent  Bile ducts and hepatic arterioles are normal Top Differential Diagnoses…

 Once known etiologies are excluded, then considered idiopathic • By mid-2000s, idiopathic neonatal hepatitis (INH) comprised only 15-30% of neonatal cholestasis due to increased ability to detect and diagnose metabolic and…

 Often classified as having high-grade dysplasia given architectural complexity • Neoplastic cells have abundant granular eosinophilic cytoplasm with large nuclei, prominent nucleoli • Both intracytoplasmic and intercellular lumina found, many containing mucin,…