Mohs' micrographic surgery for basal cell carcinomas on the eyelids and medial canthal area. I. Characteristics of the tumours and details of the procedure.

PURPOSE: To analyse the characteristics of eyelid basal cell carcinomas excised using Mohs' micrographic technique.

METHODS: Sixty-six eyelid basal cell carcinomas were excised using Mohs' micrographic technique. The tumours were classified into four subtypes; morpheiform, intermediate, nodular/micronodular and superficial. Data on previous treatment of the tumours were retrieved.

RESULTS: Thirty-two tumours (48%) were primary, 8 tumours (12%) were incompletely excised using conventional excision surgery and 26 tumours (39%) were recurrent. Nineteen of the 26 (73%) recurrent tumours and 14 of the 32 (44%) primary tumours were nodular/micronodular. To achieve radical excision, superficial tumours needed an average of 2.0, nodular/micronodular 2.5, intermediate 2.0 and morpheiform tumours 2.9 excisions.

CONCLUSIONS: Eyelid basal cell carcinomas with ill-defined borders or recurrent tumours are well suited for Mohs' micrographic surgery. The extensions of the tumours are difficult to determine even in some less aggressive subtypes such as superficial and nodular/micronodular basal cell carcinomas.