Dermal dendrocyte hamartoma with stubby white hair: a novel connective tissue hamartoma of infancy.

A previously undescribed hamartoma with stubby white hair was observed in a 1-week-old girl. A deep red, soft nodule with fine wrinkles was present on the back. White bizarre short thick hairs with irregular exterior cuticular squamae were noted. The main cells proliferating in the nodule were fibroblast-like spindle cells that had dendrites and showed positive staining for CD34 antigen. These cells surrounded vessels and nerves. In addition, there were immature hair follicles, relatively thick-walled small vessels, and small adipose cells with fine connective tissue. This hamartoma was considered to be a dermal dendritic cell hamartoma originating from CD34-positive cells.