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 exc ised using Mohs' micrographic technique. Methods. Sixty-six eyelid basal cell carcinomas were excised using Mohs' mi crographic technique. The tumours were classified into four subtypes; morph eiform, intermediate, nodular/micronodular and superficial. Data on previou s treatment of the rumours were retrieved. Results: Thirty-two tumours (48%) were primary, 8 tumours (12%) were incomp letely excised using conventional excision surgery and 26 rumours (39%) wer e recurrent. Nineteen of the 26 (73%) recurrent rumours and 14 of the 32 (4 4%) primary tumonrs were nodular/micronodular. To achieve radical excision, superficial tumours needed an average of 2.0, nodular/micronodular 2.5, in termediate 2.0 and morpheiform tumours 2.9 excisions, Conclusions: Eyelid basal cell carcinomas with ill-defined borders or recur rent tumours are well suited for Mohs' micrographic surgery. The extensions of the tumours are difficult to determine even in some less aggressive sub types such as superficial and nodular/micronodular basal cell carcinomas.