Multifocal recurrent basal cell carcinoma following primary tumor treatment by electrodesiccation and curettage.

Eight recurrent basal cell carcinomas and their adjacent scars, which were previously treated with electrodesiccation and curettage, were completely excised by Mohs micrographic surgery and then studied by serial vertical sections. Through the study of an average of 291 serial sections of each recurrent tumor, it was found that four of eight recurrent basal cell carcinomas contained multiple foci of unconnected tumor. It is concluded that iatrogenic multifocality of recurrent basal cell carcinoma previously treated with electrodesiccation and curettage is common. Complete excision of the recurrent basal cell carcinoma and its adjacent scar is supported in view of the high risk of multiple unconnected tumor foci.