Hepatic Mesenchymal Hamartoma
Also written as: HMH — Hepatic Mesenchymal Hamartoma
A benign cystic hepatic tumour of early childhood composed of loosely arranged mesenchymal stroma, bile ducts, and hepatocyte cords, typically presenting as a large abdominal mass.
Full Definition
Hepatic mesenchymal hamartoma (HMH) is the second most common benign hepatic tumour of childhood after infantile haemangioma, arising predominantly in children under 2 years of age. Grossly, it presents as a large, multicystic mass that may reach several kilograms, causing abdominal distension. Histologically, it consists of loosely myxoid mesenchymal stroma containing branching bile ducts and hepatocyte plates in variable proportions, often with cystic degeneration. A subset of HMH carries chromosomal translocations involving 19q13.4, a region also implicated in embryonal sarcoma of the liver, suggesting a possible pathogenic relationship. Editors should note that 'mesenchymal hamartoma' refers specifically to this hepatic entity and should not be applied loosely to other hepatic hamartomatous lesions.
Usage
Usage note: Do not abbreviate to 'hamartoma' without the qualifying adjectives 'hepatic mesenchymal,' as this may cause confusion with other hamartomatous lesions at other sites.
In Context
- "The multiloculated cystic hepatic mass resected from the 14-month-old showed the characteristic loose myxoid stroma of hepatic mesenchymal hamartoma." — Paediatric surgical pathology report
- "Hepatic mesenchymal hamartoma should be differentiated from hepatoblastoma both clinically and histologically, as the former is benign and the latter requires chemotherapy." — Paediatric pathology review article