Amelanotic melanoma of the lung and brain with fenestrated intrinsic tumor capillaries.

Tissue from an amelanotic melanoma which involved the lung and brain was studied by electron microscopy. Endothelial fenestrae were found in the intrinsic tumor capillaries at both locations, a finding which does not appear to have been previously reported for amelanotic melanoma. Pitfalls in the diagnosis of this rare tumor are discussed.