[Hamartoma oligemicus]

Naevus oligemicus is a rare affection caused by selective vasoconstriction of the deeper vessels ("thermal" skin blood flow), with respect of the superficial vascular plexus ("nutrient" blood flow). We report the fourth case.

A 45 year-old man presented erythematocyanotic lesions with sensation of coolness on the abdomen and the thighs. These lesions had first been noted by the patient 3 years earlier. Physical examination and laboratory investigations were normal. Histology of a lesion revealed a non-specific superficial dermatitis. Result of skin surface thermometry of both areas showed that the surface temperature of the involved skin was up to 2 degrees C lower than the surrounding control skin.

We don't know why there is a selective vasoconstriction of the deeper vessels and not of the superficial vascular plexus. Naevus oligemicus belongs to the pharmacological naevus group because of the absence of any histologic vascular abnormality. The functional abnormality has not been identified. This could be explained either by increased sympathetic vasoconstrictor tone in the autonomic sympathetic vasoconstrictor nerves supplying the deeper thermoregulatory vasculature in the affected skin, or by increased sensitivity of these vessels to vasoconstrictor catecholamines.