Guidelines for Reporting and Managing Histological Regression in Melanoma

Definition and Histopathological Criteria

• Regression in melanoma is defined as the histological replacement of tumor cells by fibrosis, lymphocytic inflammation, melanophages, and neovascularization, and must be documented as a mandatory prognostic parameter in pathology reports. 1
• Segmental replacement of melanoma by fibrosis is the most reproducible histological criterion, showing the least inter‑observer variation among descriptive terms. 2

Mandatory Reporting Requirements

• The NIH Consensus Conference (1992) and the French Consensus Conference (1995) mandate that every melanoma pathology report include the presence and extent of regression. This requirement is a standard, non‑optional element of the report. 1
• Pathology reports should explicitly state whether regression is present or absent. 2

Clinical and Surgical Management

• Partial biopsies of melanocytic lesions should be avoided because regression can lead to sampling error and prevent accurate staging of the melanoma. (Evidence based on expert consensus.) 2
• Scalpel excision, rather than laser or electro‑coagulation techniques, should be used to preserve tissue integrity for proper assessment of regression and other prognostic factors. (Expert consensus.) 1