Sequence of melanocyte migration into human scar tissue

Scars of human skin can on occasions provide a very useful ancillary method of identification of an unknown deceased. If the age of any visible scars can be estimated objectively, then this might be of some assistance in the identification procedure. Melanocytes migrate into scar tissue as it ages and their number within the epidermal basal layers alters during the maturation of a scar. A total of 64 scar samples, all from previous surgical sites, were taken in the course of autopsies. Each scar was stained by the H & E method and by an immunohistochemical method using polyclonal S100 antibody. The number of melanocytes in the basal layer was counted in the epidermis overlying the scar and in the adjacent epidermis. This ratio was matched with the documented age of the scar and a statistical evaluation was carried out matching the chronological age of the scars to the melanocyte/basal epidermal cells ratio. Scars with a duration between 1 and 3 years showed a mean ratio of 1.85 and a maximum ratio of 1.94, 1.8 years after a surgical operation. The number of basal melanocytes declined thereafter and reached that of the adjacent epidermis after about 10 years. The immunohistochemical detection of melanocytes can be used for the diagnostic ageing of scars which may be a valuable contribution to improve the identification of unknown deceased persons.