Background: It has been proposed that the management of incompletely excised recurrent basal cell carcinomas (BCCs)-should depend on their histological app earance, and that nonaggressive recurrent BCCsmay not require re-excision. Obj ectives: To determine the histological evolution of recurrent BCCs. Methods: In a 14- year retrospective study analysing histological sections of recurrent BCC s, 390 specimens from 191 patients were blindly classified by three physicians i nto aggressive and non-aggressive types according to Sexton’s classification . Initial histological sections were available for 33 of the recurrent BCCs. Des criptive analysis was performed. Results: Eight of 33 (24% ) recurrent BCCs bec ame histologically more aggressive. Four of 20 (20% ) originally nonaggressive BCCs became aggressive during recurrence and four of 13 (31% ) originally aggre ssive BCCs showed a more aggressive component during recurrence. These incomplet ely excised aggressive BCCs were sited in periorbital and perinasal areas and on the cheek, and were re-excised. Conclusions: Management of incompletely excis ed nonaggressive BCCs (nodular or superficial types) is still a matter of debate . Previously reported studies have shown recurrence in < 10% of nonaggressive incompletely excised BCCs. Our study showed that rare recurrences of these initially nonaggressive BCCs showed an aggressive component in 20% of cases. These results suggest that initially nonaggressive incompletely excised B CCs do not require re-excision except if they are located in sites with a poor prognosis. Background: It has been proposed that the management of incompletely recived basal cell carcinomas (BCCs) -should depend on their histological app earance, and that nonaggressive recurrent BCCsmay not require re-excision. Obj ectives: To determine the histological evolution of recurrent BCCs . Methods: In a 14-year retrospective study of histological sections of recurrent BCCs, 390 specimens from 191 patients were blindly classified by three physicians i nto aggressive and non-aggressive types according to Sexton’s classification. Initial histological sections were available for 33 of Four of 20 (20%) originally nonaggressive BCCs became aggressive during the recurrence and four of 13 (31%) of those originally recurrent BCCs. Des criptive analysis was performed. Results: Eight of 33 (24%) recurrent BCCs bec ame histologically more aggressive. aggre ssive BCCs showed a more aggressive component during recurrence. These incomplets ely excised aggressive BCCs were sited in peri orbital and perinasal areas and on the cheek, and were re-excised. Conclusions: Management of incompletely excis ed nonaggressive BCCs (nodular or superficial types) is still a matter of debate. Previously reported studies have shown recurrence in <10% of nonaggressive incompletely excised BCCs. Our study showed that rare recurrences of these initially nonaggressive BCCs showed an aggressive component in 20% of cases. These results suggest the initially nonaggressive incompletely excised B CCs do not require re-excision except if they are located in sites with a poor prognosis.