Mediastinal epithelioid hemangioendothelioma with abundant spindle cells and osteoclast-like giant cells mimicking malignant fibrous histiocytoma

ABSTRACT: Epithelioid hemangioendothelioma is a relatively uncommon lesion usually presenting in soft tissues. The occurrence in the mediastinum is exceptional rare. Histologically, this tumor is characterized by epithelioid cells with intracytoplasmic vacuoles in a hyalinized or mucinous stroma. Occasionally, spindle cells or osteoclast-like giant cells can be observed. Herein, we present a case of epithelioid hemangioendothelioma in a 38 year-old Chinese male. The tumor was predominantly composed of abundant spindle cells with marked atypia and scattered osteoclast-like giant cells reminiscent of malignant fibrous histiocytoma. The unusual histological appearance can pose a great diagnostic challenge. It may be easily misdiagnosed, especially if the specimen is limited or from fine-needle aspiration. VIRTUAL SLIDES: http://www.diagnosticpathology.diagnomx.eu/vs/5804918529726307