Aggressive Systemic Mastocytosis Resulting in Hepatic Fibrosis and Non-Cirrhotic Portal Hypertension

Aggressive systemic mastocytosis [ASM] is a rare hematologic disorder characterized by mast cell infiltration of extracutaneous organs. Hepatic involvement is uncommon and rarely progresses to fibrosis or portal hypertension. We present a 60-year-old male with abdominal distension, hepatosplenomegaly, and thrombocytopenia, ultimately diagnosed with ASM after bone marrow and liver biopsies confirmed mast cell infiltration. Despite treatment with avapritinib, he developed noncirrhotic portal hypertension and expired due to multisystem complications. This case highlights the need to consider ASM in patients with cryptogenic liver disease and underscores the importance of early diagnosis and multidisciplinary management in improving outcomes.