[Morphological studies of papillomatosis confluens et reticularis in diabetes mellitus].

Macroscopically papillomatosis confluens et reticularis (PCR) is a typical dermatosis with three different clinical forms. Histologically the characteristics are orthokeratosis, papillomatosis and hyperpigmentation. A case report of PCR and diabetes mellitus reveals further histological factors, these being interstitial and intracellular edema in the epidermis and a homogenization of collagen and rarefication of elastic fibres. Ultrastructurally intracytoplasmic lipid vacuoles in the basal and suprabasal squamous cell layer were a prominent feature. These findings could be demonstrated in normal and PCR skin, which until now has not been described in the skin of diabetes mellitus patients. The question arises if PCR can be interpreted as a symptom of a fat metabolism disease in which unknown additional factors may play a role.