Evaluating invasive cutaneous melanoma: is the initial biopsy representative of the final depth?

Background: An accurate initial biopsy of the deepest portion of the melanoma is vital to the management of patients with melanomas.

Objective: Our goal was to evaluate the accuracy of preliminary biopsies performed by a group of predominantly experienced dermatologists (n = 46/72).

Methods: A total of 145 cases of cutaneous melanoma were examined retrospectively. We compared Breslow depth on preliminary biopsy with Breslow depth on subsequent excision. Was the initial diagnostic biopsy performed on the deepest part of the melanoma?

Results: Of nonexcisional initial shave and punch biopsies, 88% were accurate, with Breslow depth greater than or equal to subsequent excision Breslow depth. Both superficial and deep shave biopsies were more accurate than punch biopsy for melanomas less than 1 mm. Excisional biopsy was found to be the most accurate method of biopsy.

Conclusions: Deep shave biopsy is preferable to superficial shave or punch biopsy for thin and intermediate depth (<2 mm) melanomas when an initial sample is taken for diagnosis instead of complete excision. We found that a group of predominantly experienced dermatologists accurately assessed the depth of invasive melanoma by use of a variety of initial biopsy types.