Background: Keloids cause significant physical and psychological morbidity. Intralesional cryosurgical technique has been shown to bring about significant improvement in keloids, but its mechanism is unclear.

Objective: The aim of the present study was to evaluate the effect of intralesional cryosurgery on keloid fibroblast proliferation by immunohistochemical assessment of cell proliferation before and after treatment and its relation to therapeutic response of keloids.

Materials and methods: Keloids from 10 patients were treated with intralesional cryosurgery and sessions were repeated at 3-week intervals according to clinical response. Biopsies were obtained from the lesions before and 3 weeks after the second treatment session. Immunohistochemical detection of the expression of proliferating cell nuclear antigen (PCNA) in lesions was done to assess changes in keloid fibroblast proliferation after treatment.

Results: The results showed complete flattening in 8 lesions and significant volume reduction (> 75 %) in 2 lesions. Considerable decrease in PCNA expression was detected in keloid tissues after treatment.

Conclusion: The inhibition of keloid fibroblast proliferation could be one of the mechanisms for the therapeutic effect of intralesional cryosurgery in keloids.