Keloid histopathology after intralesional cryosurgery treatment

Keloid presents a great healthcare challenge. The patients suffer from aesthetic disfiguration and occasionally from pruritus, pain and discomfort. Although various treatments are recommended, a single, highly effective treatment represents a great clinical need.

The cellular events and histopathology that follow intralesional cryosurgery were evaluated including cell proliferation, the number of cells expressing fibroblast markers, collagen synthesis and organization and mast cell infiltration.

Biopsies were collected before and after intralesional cryoneedle procedure. Collagen structure was evaluated with confocal microscopy. Mast cells, blood vessels and cell proliferation were evaluated using immunohistochemistry.

Keloids contain abnormally thick collagen bundles, organized in swirls comprising closely bound fibrils. After intralesional cryosurgery, the collagen bundles lost their swirl structure, the thickness of the collagen layer decreased, and the bundles became more compact with less space between the fibres. A clear distinct transition zone separated the treated from the unaffected area. The frozen tissue was devoid of proliferating cells and mast cells whereas the number of blood vessels remained unaltered. Most of the fibroblasts expressed all tested myofibroblast markers although some exclusively expressed one and not the other. Few nuclei were observed in the affected area after treatment and very few of them expressed any fibroblast markers.

Intralesional cryosurgery resulted in major changes in collagen structure and organization. The treatment reduced the number of proliferating cells, of myofibroblasts and of mast cells. These results may explain the reduction in no-response rate and the amelioration of the clinical symptoms after intralesional cryosurgery treatment.