Histiocytoma

Histiocytomas are benign, reactive reproductions of fibroblasts.

They develop as tight, painless, single or multiple, dermal nodules with a maximum size of 5 mm.

Mostly they occur on the extremities. Their colour varies from reddish brown to blue-black.

https://de.wikipedia.org/wiki/Dermatofibrom _{(Wikipedia CC-by-sa-3.0)}