Background: Patients who are referred for Mohs surgery after pre-operative biopsy has been performed show in some cases no clinical or pathological evidence of tumour persistence. We have previously shown that 25% of these patients show no residual skin cancer either basal cell carcinoma or squamous cell carcinoma. The reasons for 'disappearance' of the tumour may be true non-persistence or false non-persistence because of wrong-site Mohs surgery.
Objective: To determine the incidence of residual basal cell carcinoma after shave biopsy of primary nodular basal cell carcinoma prior to Mohs micrographic surgery.
Methods: A prospective unblinded study was performed on patients undergoing Mohs surgery for primary nodular basal cell carcinoma. The tumour was removed as a shaved excision using a No. 15 blade at the clinical borders like a shave biopsy (Mohs shave). The bases of the tumors were excised and then sectioned vertically at the middle and cut to the periphery at 10-15 μm intervals till the edge.
Results: Fifty-one patients were evaluated. In 40 patients, residual basal cell carcinoma was found at the base of the shave excision site (78.4%).
Conclusions: Pre-operative shave biopsy performed during Mohs surgery for primary nodular basal cell carcinoma is 'curative' in 22% of the patients.
© 2010 The Authors. Journal of the European Academy of Dermatology and Venereology © 2010 European Academy of Dermatology and Venereology.