Primary pseudomyogenic haemangioendothelioma of bone

Abstract

Pseudomyogenic haemangioendothelioma is a recently described vascular neoplasm that occurs most commonly in the soft tissue of distal extremities of young adults. Occurrence outside the somatic soft tissue has not been described thus far. We present here a unique case of pseudomyogenic haemangioendothelioma that arose in the long tubular bones of the lower extremity. The initial open biopsy was interpreted as a fibrous histiocytoma. However, the curettage specimen showed prominent epithelioid cytomorphology with a striking rhabdomyoblast-like appearance. By immunohistochemistry, the linear membranous staining of CD31 was highly suggestive of endothelial differentiation of the tumour cells. To the best of our knowledge, this case represents the first example of primary pseudomyogenic haemangioendothelioma of bone. Clinical and pathological correlation with application of immunohistochemistry is mandatory in establishing the correct diagnosis and excluding tumours with overlapping features.