OBJECTIVETo study the clinicopathological characteristics of hepatic angiomyolipoma (HAML) and to evaluate the correlation between clinicopathological parameters and tumor subtypes.

METHODSRetrospective analysis of clinicopathological features was conducted in 182 cases of HAML.

RESULTSHAML patients were predominantly female (M:F=1:4) and most commonly presented with non-specific symptoms. The median age at diagnosis was 46 years, ranged from 17 to 77 years. Tumor diameter was ranged from 0.3 to 32.0 cm with an average of 5.0 cm. Majority of the tumor was epithelioid type (112/165, 67.9%). Extramedullary hematopoiesis, multinucleated giant cells, intranuclear inclusions, nucleolus, cellular atypia, invasive growth pattern, multiple masses, hyperpigmentation and purpura-like changes mostly occurred in the epithelioid type (P<0.05). Extramedullary hematopoiesis was commonly seen in HAML, the significance of which was still uncertain.

CONCLUSIONSMost of HAML are epithelioid type, characterized by a proliferation of predominantly epithelioid cells, in which extramedullary hematopoiesis is commonly seen. Some morphologic features that may predict malignant such as necrosis, mitotic figures, and tumor emboli are only found in the epithelioid HAML. Mitotic activity, tumor necrosis, tumor thrombus, giant cells, periportal invasion, multiple lesions and tumors size over 10 cm are closely related with tumor recurrence and metastasis.