Correlation Between Original Biopsy Pathology and Mohs Intraoperative Pathology

Abstract

A substantial discrepancy was observed between preoperative biopsy and intraoperative pathology, including a significant portion tumors that became more aggressive. These results suggest that treatment modalities without margin control may not provide adequate treatment for a considerable number of NMSC based on preoperative tumor type alone.

Comparison of basal cell carcinoma subtypes observed in preoperative biopsy and Mohs micrographic surgery

“… 17 In Stiegel's study, among the tumors that were reclassified as more aggressive, 84% had been sampled by shaving biopsies and 14%, punch biopsy (the others were not reported). 16 However, in a previous study, Haws observed only a slight superiority of punch biopsy over shaving in the correct detection of BCC subtypes (89% vs. 81%). 8 …”

“…Izikson et al observed an agreement of 49%; Stiegel, 46.7%; Orengo, 42.7%; and the present study, 40.5%. 15 , 16 , 17 The rigorous classification of the histopathological subtypes adopted in the current study may have influenced the lower agreement. The presence of any distinct subtype area, even if minimal, was considered.…”

“…Another important observation is that Stiegel did not debulk the tumors at MMS for additional evaluation, thus reducing the amount of tissue that was compared with the preoperative biopsy. 16 This measure probably increased the possibility of agreement of the findings. Genders et al conducted the only study in which the MMS block was completely sectioned and was not debulked, which allowed the observation of the largest possible tumor sample.…”

“…Previous studies that made this same analysis, comparing preoperative biopsy with MMS findings, found values of 19%, 27%, and 36%. 15 , 16 , 17 In a recent review on the subject that included studies with WLE and MMS, Singh found an upstaging rate of 31%. 27 Possible explanations for the lower rate of upstaging in the present study are the fact that, in the United States, where the other studies were performed, the insurance coverage for MMS is much broader, which is why non-aggressive tumors are frequently treated with the technique.…”

“…In most other studies, data were collected from a database, or the assessment was not blind. 9 , 16 When assessing the WLE or MMS slides, a non-blinded evaluator may be influenced by the result of the initial biopsy.…”