An unusual case of cavernous haemangioma of the liver presenting as an infiltrative lesion

Cavernous haemangiomas are the most common primary tumour of the liver and are usually a straightforward radiological and histopathological diagnosis, typically forming a single well-circumscribed lesion composed of numerous medium-sized to large vascular spaces lined by bland endothelial cells with intervening fibrous stroma. We present an unusual case of a cavernous haemangioma which presented as an infiltrative lesion. The radiologic appearances were not typical of a cavernous haemangioma and a range of neoplastic differential diagnoses were suggested, so the lesion was resected via hemi-hepatectomy. Histology showed multiple abnormal thick and thin-walled vascular spaces extending irregularly through hepatic parenchyma along the portal tracts. This atypical appearance raised the differential diagnosis of angiosarcoma, Kaposi sarcoma and the recently described entity of hepatic small vessel neoplasm. The large vascular spaces, fibrous vessel walls, bland, flattened endothelial lining and low proliferative index were used to exclude these differentials.