Awareness of the clinicopathological hallmarks is important to avoid underdiagnosis of MCAH and the immunohistochemical features may contribute to understanding the pathogenesis of this rare disease.

Backgrounds Striae distensae (SD) has a known psychological impact due to the resulting cosmetic disfigurement. Many treatment modalities have been used over the years, but no standard interventions or evaluation methods have been proposed to date. Objective We compared the efficacy and safety of non-insulated microneedle radiofrequency (NIMRF) and fractional CO 2 laser treatments of SD by objective measurements with dermoscopy and VISIA. Methods Fourteen females with severe SD were enrolled. These subjects had been treated three sessions of NIMRF and fractional CO 2 laser for the right and left abdomen, respectively. Dermoscopy and VISIA imaging data, and photographs were collected at baseline and 2 months after the last treatment session. The global aesthetic improvement scale (GIAS) was scored by patients, and blinded investigators, pain score and satisfaction score were also documented. Any side effects were recorded. Results Ten patients completed the study. The GIAS from investigators and patients showed an overall improvement but without a significant difference (P = 0.18, P = 0.17, respectively). The decreased width measured by dermoscopy was between 5% and 32% (right side) and 6-31% (left side). There was no significant difference between both sides in either the per-protocol or intention to treat analyses (P = 0.149, P = 0.161, respectively). The mean pain score was 5.35 and 2.35 on the right side and left side, respectively, which was significant (P = 0.0016). Post-inflammatory hyperpigmentation (PIH) manifested in six patients on their left sides and four patients on their right sides. In most cases, this had resolved by the 3-month follow-up. Conclusion Non-insulated microneedle radiofrequency and fractional CO 2 laser are both effective and safe treatment options for SD. PIH is a possible side effect but is more likely with fractional CO 2 laser treatment. However, it clears up in most cases. Dermoscopy and VISIA are both convenient, digitalized methods of tracking subtle changes and monitoring the efficacy of SD treatments.

Awareness of the clinicopathological hallmarks herein may be important to avoid underdiagnosis of PAD and may contribute to understanding the pathogenesis of this rare disease.