Successful Treatment of MEK Inhibitor-Induced Paronychia in Neurofibromatosis with Photodynamic Therapy: A Case Report and Review of the Therapeutic Options.

Background/Objectives: Selumetinib, a MEK1/2 inhibitor, is commonly used for treating neurofibromatosis type 1 (NF1) and is associated with cutaneous side effects such as paronychia and periungual granulomas. These complications can be painful and difficult to manage, often leading to the discontinuation of treatment. The objective of this study was to evaluate the effectiveness of photodynamic therapy (PDT) as a novel treatment for MEKi-induced paronychia in a patient with NF1. Methods: We present a case report of an 18-year-old patient with NF1 who developed painful periungual granulomas on the toenails after 12 months of Selumetinib therapy. PDT was administered using methyl aminolevulinate (METVIX®) as the photosensitizing agent, followed by treatment with a red LED light source (630 nm, 37 J/cm2 for 8 min and 30 s). The patient was followed up for two months post-treatment and then at two years. Results: After a single PDT session, the patient exhibited complete clinical remission of the periungual granulomas and associated pain. No recurrence of the lesions was noted during the two-year follow-up. The patient tolerated the procedure well, reporting only mild discomfort during treatment. Conclusions: PDT appears to be an effective, minimally invasive treatment for Selumetinib-induced paronychia and periungual granulomas. This case demonstrates that PDT can provide a complete resolution of symptoms with a single treatment session, offering an alternative to more invasive procedures. Further studies with larger cohorts are needed to establish PDT as a standard treatment option for this condition.