ANGIOKERATOMA corporis diffusum is only rarely described in the usual textbooks. This is not surprising, since only about 20 characteristic cases of angiokeratoma corporis diffusum have been observed since its first description in 1898. However, it would be wrong to consider this skin condition a dermatological curiosity. Investigations during the past few years have shown that in all probability this cutaneous anomaly will have to be considered as a sign of an internal disease unknown so far. It is by no means inconceivable that the rarity of angiokeratoma corporis diffusum (as far as I know, no case has yet been described in America) is due to the fact that remarkably few dermatologists seem to be familiar with this condition. The purpose of this paper is to draw attention once more to the skin disorder concerned. At the same time, a description of the internal anomalies which have recently been