Liver, Epithelioid hemangioendothelioma, CD31 stain

Epithelioid hemangioendothelioma (EHE) is a low grade malignant vascular tumour. This tumour commonly occurs in a younger population (typically 30-50 years old) and may arise in various places in the body including soft tissues and visceral organs, particularly within the liver and the lung.

The tumour is characteristically composed of poorly vaso-formative epithelioid cells with mild nuclear enlargement growing in small nests, cords, or single cells within fibrous stroma. In the liver, a characteristic feature is increasing tumour cellularity towards the edges of the lesion. The tumour reacts with vascular markers such as ERG-1, CD34 and CD31 stains.

Virtually all EHEs are defined by one of two recurrent translocations, the t(1;3) WWTR1-CAMTA1 fusion gene (in up to 90% of cases) as well as YAP1-TFE3 in a smaller number of cases.

This slide shows CD31 stain. See Related Content for H&E and ERG-1 stains

See Related Content for references:
1) Antonescu, C. Mod Pathol. 2014 Jan
2) Flucke, U. et al. Diagn Pathol. 2014 Jul 1;9:131