Why People Get Liver Cysts
Origin and Development
Simple hepatic cysts arise from aberrant bile duct cells that develop during embryonic development, though the exact mechanism remains incompletely understood. 1
The pathogenesis involves:
Embryonic bile duct malformation: Cysts originate from bile duct cells that become separated from the normal biliary tree during fetal development, forming isolated fluid-filled cavities lined with epithelium 1
Benign developmental anomaly: These are congenital lesions that typically remain stable throughout life, though the reason why some cysts grow while others remain unchanged is unclear 2
Clinical Significance and Natural History
Simple hepatic cysts are extremely common benign lesions:
Prevalence: Found in up to 18% of the general population, making them one of the most common incidental findings on abdominal imaging 3
Typical course: Most follow an indolent course without significant size changes over time 2
Growth patterns: While cysts may occasionally enlarge, the mechanism driving growth in some cysts versus stability in others remains unknown 2
Other Types of Hepatic Cystic Lesions
Beyond simple cysts, several other cystic entities can develop:
Biliary hamartomas: Small (2-10 mm) cystic lesions arising from fibrocollagenous stroma with biliary elements, creating a "starry sky" appearance on imaging 2
Peribiliary cysts: Small (<1 cm) cysts with perihilar distribution, often associated with portal hypertension and cirrhosis 2
Polycystic liver disease: Genetic condition with multiple cysts throughout the liver parenchyma 2
Key Clinical Pitfall
Do not confuse simple hepatic cysts with biliary cystadenomas based on imaging alone. Radiologic reports frequently include "rule out biliary cystadenoma" in the differential diagnosis, which can lead to unnecessary anxiety and surgical intervention in asymptomatic patients, despite the fact that histopathology consistently confirms benign simple cysts 4. In one series, 75% of asymptomatic patients who underwent surgery based on a radiologic diagnosis of cystadenoma had simple cysts on final pathology 4.
Management Implications
The benign embryonic origin of simple hepatic cysts has important clinical implications:
No malignant potential: Simple cysts have zero risk of malignant transformation 1
No surveillance needed: Asymptomatic cysts require no follow-up imaging regardless of size, as they pose no threat to morbidity or mortality 2, 5
Symptom-driven intervention only: Treatment is reserved exclusively for symptomatic cases causing abdominal discomfort, pain, or compression of adjacent structures 2, 3