It is diagnosed by a microscopic examination of the placenta. Commonly used criteria from Altshuler are: "a minimum of 10 villi, each with 10 or more vascular channels, in 10 or more areas of 3 or more random, non-infarcted placental areas when using a ×10 ocular." The Altshuler criteria are not theoretically rigorous, as they do not define the area. Normal villi have up to five vascular channels.
Chorangiosis
Diabetic angiopathy
Arteriolosclerosis
Lipodermatosclerosis
Microangiopathy
Universal angiomatosis
Bacillary angiomatosis
Angiolathyrism