Demystifying Idiopathic Adulthood Ductopenia: Diagnosis and Differential Diagnosis

Idiopathic adulthood ductopenia (IAD) is a rare chronic cholestatic liver disorder characterized by progressive loss of interlobular bile ducts in the absence of an identifiable etiology. Its histologic hallmark, ductopenia, is nonspecific and occurs across many cholestatic disorders, which complicates its recognition. IAD is therefore a diagnosis of exclusion, requiring thorough evaluation to rule out immune-mediated cholangiopathies, infections, genetic or metabolic diseases, drug-induced injury, and neoplasia. Advances in molecular diagnostics have increasingly uncovered monogenic cholangiopathies in adults previously classified as IAD, thereby narrowing the truly idiopathic category. In this article, we provide a comprehensive review of the disease, with emphasis on its clinical presentation, histopathologic characteristics, differential diagnoses, and emerging concepts.