History:

 Acanthosis Nigricans

Clinical. This condition is more easily diagnosed clinically than perhaps through histology. There is the more luxuriant variant that is associated with internal malignancy, but most cases are associated with hyperinsulinism and very often seen with obesity or metabolic syndrome. They may also be seen with polycystic ovary syndrome and in Downs’s syndrome. Histology shows mild acanthosis with hyperkeratosis and papillomatosis. Looking carefully at the dermal papillae the projections of these are covered by a very thin layer of epidermis. The intervening acanthosis is covered with mild hyperkeratosis. The rete ridges are not elongated. The hyperkeratosis is most marked between the papillomatosis rather than above it.

Main DDs are Seb K , Confluent and reticulated papillomatosis and an Epidermal nevus but clinical corelation soon excludes these conditions

   Virtual Slide of Acanthosis Nigricans