Local Recurrence Rates of Skin Tumors After Resection With Complete Circumferential Peripheral and Deep Margin Assessment-Identification of High-Risk Entities.

Background: The local recurrence rates of malignant skin tumors after micrographic controlled surgery using complete circumferential peripheral and deep margin assessment (CCPDMA) are reported to be low. However, in daily practice, tumor entities with a significantly higher recurrence rate are found.

Objective: The aim of the investigation was to identify these high-risk tumors to develop approaches for risk stratification.

Patients And Methods: We included different malignant tumors that were surgically treated and examined with CCPDMA using paraffin sections and H&E staining. Re-excisions were performed until the tumor was completely removed.

Results: Ninety-nine thousand three hundred seventy-two tumors were included in the study; the follow-up period was 4 years (median). Eight tumor entities were identified as high-risk entities, showing a significantly higher local recurrence rate of over 20%: desmoplastic squamous cell carcinoma, desmoplastic melanoma, Merkel cell carcinoma, microcystic adnexal carcinoma, pleomorphic sarcoma, liposarcoma as well as angiosarcoma, and extramammary Paget's disease.

Conclusion: Complete circumferential peripheral and deep margin assessment allows complete control of the resection margins and enables skin-sparing resections with low recurrence rates for basal cell carcinomas, nondesmoplastic squamous cell carcinomas, lentiginous melanomas, and dermatofibrosarcoma protuberans. However, other tumors show significantly higher recurrence rates and therefore need to be classified as high-risk tumors.