Clinicopathologic features and prognostic factors in hepatic epithelioid hemangioendothelioma.

Hepatic epithelioid hemangioendothelioma (EHE) is a rare sarcoma with variable biological behavior. We analyzed 19 cases to assess whether risk stratification criteria for soft tissue EHE apply to hepatic EHE. Clinicopathologic features were analyzed, including growth pattern, nuclear grade, tumor architecture, cytomorphology, stroma, and mitotic counts. The majority of patients were women (74%) with a mean age of 52 years. Common histologic features included an infiltrative growth pattern (63%), epithelioid morphology (53%), low nuclear grade (53%), myxohyaline stroma (74%), and non-solid architecture (63%). Metastatic rate (21%) and mortality rate (21%) were comparable to soft tissue EHE. In univariate analysis, an infiltrative border and necrosis were associated with metastatic disease or recurrence. When comparing the subgroup of patients who died of disease (n = 4) against those who were alive or died of unrelated causes (n = 15), the former small subgroup had significantly large tumors (median tumor size 13 cm vs 2 cm, p = 0.03) a spindled morphology (p = 0.018) and necrosis (p = 0.035). Notably the mitotic counts did not predict outcome. Although hepatic EHE generally demonstrates indolent behavior, recurrence and metastasis are possible. In this small cohort, tumor size correlated with a worse prognosis, mirroring soft tissue EHE, but high mitotic count did not. Thus, assessing tumor size and spindled morphology may provide potential indicators of high-risk behavior, though these features require validation in larger cohort.