Surgical versus pathological excision margins—an excision too far?

A common observation by clinicians who surgically excise skin pathology is the discrepancy between the measured size of the surgical specimen and that of the measurements reported by the examining pathologist. This discrepancy can often be the difference between whether, in the case of skin malignancies, the patient requires further wider excision, follow-up and, in cases where relevant, discharge. Could it therefore mean that patients are needlessly undergoing further excisions that could be avoided with more careful attention to specimen measurements and specimen ‘shrinkage,’ both surgically and pathologically? We measured the length and width of skin lesions excised pre- and post-operatively and compared these measurements with the reported histopathological measurements. A significant difference in length (p = 0.000) and width (p = 0.001) exists between pre- and post-operative measurements. No significant difference exists between post-operative and pathological measurements of length (p = 0.072) or width (p = 0.157). Length of time preserved in 10% formalin did not make a significant difference to specimen size (p = 0.47). The aim of clinicians is to excise fully all skin pathology relevant for excision, ensuring sufficient clear margins to prevent potential recurrence whilst trying to sacrifice as little ‘normal’ tissue as possible in the process. What this study helps to highlight is the fact that clinicians cannot take for granted the reported measurements on the histopathology reports, upon which subsequent clinical management on reported excision margins are often based, without taking into consideration documented excision margins and subsequent allowance for significant specimen shrinkage, often resulting, for malignancies, in further wider excisions that are potentially disfiguring, and in the authors opinion, in more cases than currently thought, unnecessary. If one also factors in the fact that malignant cells shrink less than both benign tumours and, most importantly, normal skin, then subsequent reported pathological margins may be increasingly inaccurate as the excision margins may indeed be greater.