An ultrastructural study of a nasal haemangioendothelioma.

A malignant haemangioendothelioma of the nose has been examined with the electron microscope. The tumour is predominantly poorly differentiated with only little evidence of its vascular ancestry identified. The cells are polygonal with a wide spectrum of organelles, including microfilaments. A conspicuous feature was the presence of cytoplasmic fenestrae developing into intracytoplasmic vacuolated spaces. The satisfactory progress of this patient is noted, and the value of electron microscopy in enabling an early and accurate diagnosis of this tumour to be made is emphasised.