Tumor Detection After Inflammation or Fibrosis on Mohs Levels

Background In Mohs micrographic surgery (MMS), many surgeons will take an additional level based solely on the presence of inflammation or fibrosis. Objective To determine the frequency with which this occurs and parameters predicting tumor discovery on successive levels. Materials and Methods A retrospective study was performed on 22,419 cases treated with MMS between 1996 and May 2011. The surgeons reviewed their own slides in cases where tumor was detected after a level was taken for inflammation or fibrosis. Results An additional level was taken for inflammation or fibrosis in 6,233 cases (27.8%), resulting in tumor detection in 121 cases (1.9%). Additional levels were taken for inflammation in 66.6% and fibrosis in 63.0%. Fourteen collision tumors were identified and were preceded by inflammation in 71% of cases. Discussion Factors that may predict the presence of tumor at subsequent levels include eccentrically placed or shallow first levels failing to completely encompass a previous surgical scar. The presence of dense inflammation may signal an adjacent collision tumor. Conclusion Taking an additional Mohs level when dense inflammation or fibrosis is present may be warranted to ensure complete tumor removal.