Multicentric visceral epithelioid hemangioendothelioma, with extremity dermal deposits, unusual late recurrence on the nasal bridge, and TFE3 gene rearrangement.

Abstract

Epithelioid hemangioendothelioma (EHE) is a malignant neoplasm with vascular differentiation that most frequently occurs within soft tissues, bone, lung, and liver. It is histologically typified by epithelioid or spindle cells present singly or in cords or clusters, many with cytoplasmic vacuoles that can contain intraluminal erythrocytes (in keeping with primitive vascular differentiation), within myxohyaline or sclerotic matrix. Up to 50% present with synchronous lesions as multifocal disease. The WWTR1-CAMTA1 fusion has been demonstrated in EHEs at a variety of sites and is considered to represent its genetic hallmark. We describe a case of EHE in a patient who initially presented with multiple liver and pulmonary deposits, was found to have a soft tissue lesion in the foot, and then presented with further lesions on the nasal bridge and the arm approximately 6 years after initial presentation. Interestingly, the case showed diffuse CAMTA1 expression but negative TFE3 immunohistochemically, but in contrast showed TFE3 gene rearrangement with fluorescence in situ hybridization but no evidence of WWTR1-CAMTA1 translocation. The clinical behavior of EHE is unpredictable, and this case highlights unusual anatomic, immunohistochemical, and molecular cytogenetic findings. Characterization of the genetics of EHE is important because targeted therapies toward products of the specific WWTR1-CAMTA1 gene fusion may have an impact in the near future.