Given that there are millions of cells in
a typical skin biopsy (researchers used skin from either the end of the tail or from the ear of the mouse), that translates into thousands of stem cells, each one capable of developing into any cell type of the body.
Reasons to approach a suspected case of histiocytoma more aggressively and have the suspected lesion
biopsied would be if the mass underwent rapid growth, changes in color, bleeding, itchiness, or if the lesion was not
typical and resembled other types of
skin tumors or diseases.