Optically Monitored Multimodal Treatment Incorporating Sequential Photodynamic Therapy for a Congenital Facial Melanocytic Nevus: An Exploratory Case Report with One-Year Follow-Up

Background/Objectives: Congenital melanocytic nevi in aesthetically important areas are difficult to treat because excision may require extensive surgery and cause scarring. Photodynamic therapy (PDT) may be less traumatic, but data on its use for these nevi are scarce. This exploratory case report evaluated the feasibility, tolerability, and one-year cosmetic outcome of sequential multimodal PDT with optical monitoring for a facial congenital melanocytic nevus. Methods: A 35-year-old woman with a clinically diagnosed 2 × 4 cm congenital melanocytic nevus of the face underwent 15 sessions over eight months. 5-Aminolevulinic acid (topical and sublingual), ethosomal methylene blue, and chlorin e6 were applied sequentially with sonophoresis; two methylene blue sessions were preceded by 440 nm picosecond laser treatment. PDT was performed at 635 and 660 nm (72–200 J/cm2). Video and spectral fluorescence and diffuse reflectance (hemoglobin oxygenation, blood filling) were measured before photosensitizer (PS) application, after accumulation, and after irradiation. The pigmented area was measured on standardized photographs. Results: Fluorescence predominantly increased after PS application and decreased after irradiation, consistent with accumulation and photobleaching. Oxygenation and blood filling showed no consistent treatment-related trends. The pigmented area decreased by 77.8%, from 5.4 to 1.2 cm2. No visible scarring, atrophy, or systemic adverse events occurred; transient erythema and edema resolved spontaneously. Conclusions: This case shows the technical feasibility of the protocol and a marked cosmetic reduction in visible pigmentation, not therapeutic efficacy. The single-case design, combined interventions, and lack of histological verification and a control group preclude conclusions about individual components, mechanisms, and long-term durability and safety.