Imaging and Pathologic findings of Hepatic Small Vessel Hemangioma

Hepatic small vessel hemangioma represents a distinct yet very rare pathologic entity of the liver. The entity has also been in the past referred to as adult capillary hemangioma of the liver and congenital noninvoluting hemangioma. Imaging findings are not definitive and biopsy or resection is ultimately necessary. Pathologically these represent vasoformative abnormalities with infiltrative margins that can potentially mimic hepatic angiosarcoma. Immunohistochemistry can help differentiate hepatic small vessel hemangioma from angiosarcoma. Given the infiltrative growth pattern and unknown outcomes, resection and or close follow up has been recommended. Recently the term hepatic small vessel neoplasm has been coined in view of the unknown outcomes and some concerning findings on molecular analysis. We report 2 cases of this unusual entity and describe its imaging, gross pathologic, histopathologic, and immunohistochemical features.