Congenital melanocytic nevus (CMN) is a melanocytic nevus that is either present at birth or appears during the latter stages of infancy1. Nevus sebaceous has been described as the hamartomatous locus of an embryologically defective pilosebaceous unit2. Here, we describe how we used the pinhole technique with an erbium-doped yttrium aluminium garnet (erbium : YAG) laser to treat nevi lesions in different patients.

A 25-year-old male was diagnosed with CMN on his nose at birth (Fig. 1A). Emla cream (AstraZeneca AB, Sodertalje, Sweden) was applied to the treatment area prior to starting the procedure. The erbium : YAG laser (Action Er : YAG; Lutronic Corporation, Goyang, Korea) was used in continuous-wave mode, with 1-mm spot size and output power of 0.2 mJ/cm². Multiple small holes measuring 1 mm in diameter were made on the periphery of the CMN lesion. A hydrocolloid dressing (DuoDERM Extra Thin CGF dressing; ConvaTec, ER Squibb & Sons, Princeton, NJ, USA) was applied to the lesions for ≥2 weeks after treatment. After performing 5 laser sessions at 4-week intervals, the cutaneous lesions resolved. There was no evidence of recurrence at the 1-year follow-up examination (Fig. 1B).

A 5-month-old infant was referred to our outpatient unit for CMN on the forearm (Fig. 1C). We performed the pinhole method of treatment using the erbium : YAG laser (Lutronic) in continuous-wave mode, with 1-mm spot size and output power of 0.2 mJ/cm² (Fig. 1D). After receiving 6 treatment sessions at 2-month intervals, slight superficial pigmentation persisted (Fig. 1E).

A 40-year-old woman presented with nevus sebaceous lesions on the right side of her forehead (Fig. 2A). We performed the pinhole method of treatment using the erbium : YAG laser (Lutronic) in continuous-wave mode, with 1-mm spot size and output power of 0.2 mJ/cm². After receiving 5 treatment sessions at 4-week intervals, the patient showed marked improvement with only mild hypopigmentation (Fig. 2B). No recurrence was noted at the 6-month follow-up examination (Fig. 2C).

Herein, we described how nevi lesions were effectively treated using the pinhole method. This simple method involves making multiple small holes at 2~5-mm intervals using a CO₂ laser that penetrates the epidermis and deeper dermis3. The holes produced using the pinhole method are surrounded by untreated areas that promote rapid epidermal repair, thereby reducing the downtime and likelihood of side effects4. The other advantages of performing the pinhole method with ablative lasers are that this laser is easy to use and inexpensive, as ablative lasers are usually available in most dermatology clinics. To the best of our knowledge, this is the first report on the application of the pinhole method for the treatment of CMN and nevus sebaceous, so it is difficult to compare the advantages and disadvantages of the pinhole method with those of conventional treatment methods. Therefore, it is necessary to conduct further studies with a large sample to confirm the effectiveness and safety of the pinhole method.

In conclusion, we suggest using the pinhole method with erbium : YAG laser as an alternative therapy for treating nevi lesions.