Nevus psiloliparus and aplasia cutis: a further possible example of didymosis.

Nevus psiloliparus is a distinct type of mesodermal nevus of the scalp characterized by absence or paucity of hair, and presence of an excessive amount of fatty tissue. It is considered a hallmark of encephalocraniocutaneous lipomatosis, a rare disorder comprising a variety of cutaneous, ophthalmologic, and neurologic defects. We report two infants with encephalocraniocutaneous lipomatosis with nevus psiloliparus on the scalp in close association with aplasia cutis congenita. This unusual association may be considered a further example of didymosis, for which we propose the term, didymosis aplasticopsilolipara.