This is the second report of a case of spontaneous resolution of a giant congenital melanocytic nevus, which was documented both by photographs and skin biopsies. Cases of spontaneous resolution of these lesions may represent a vigorous host response against an aberrant clone of melanocytes.

Plasminogen activator in gingival tissue was histochemically identified using a fibrin filmslide technique. Microscopic examination clearly revealed the lytic areas induced in the fibrin background; therefore, they were topographically related to the overlaying gingival section, thus facilitating the localization of plasminogen activator in the gingival tissue. Fibrinolysis was observed only on the plasminogen‐rich fibrin clot; there was no activity in the plasminogen‐free fibrin clot. This is a clear indication that the lytic areas observed were due to activation of plasminogen by tissue activator and not due to other proteolytic enzymes. Lytic activity was always associated with blood vessels and the crevice area. The degree of activity was related to the time of incubation of the tissue section with the fibrin clot.