The picosecond lasers have shown to effectively treat tattoo pigments that are intractable to previous multiple Q-switched (QS) laser treatments. Therefore we hypothesized that a picosecond laser would show better efficacy with minimal adverse events in the treatment of melasma and post-inflammatory hyperpigmentation (PIH) that are difficult to treat with conventional QS lasers. Two patients with melasma and one patient with PIH were treated with a Picosecond 755-nm Alexandrite Laser (Cyanosure, USA). All patients were Korean with skin type IV and no longer responding to QS laser treatments. Laser treatment was well tolerated in all the patients. Adverse events such as PIH were not reported during 8 weeks of follow up period. After the multiple treatment sessions, one patient reported fair improvement and two patients reported good improvement. Consistent with the clinical results, ex vivo skin model irradiated with a Picosecond 755-nm Alexandrite Laser also showed decreased epidermal keratinocyte necrosis compared with the 532-nm QS Neodymium-Doped Yttrium Aluminium Garnet Laser (Lutronic, Korea) yet decreased melanin content. In conclusion, the Picosecond 755-nm Alexandrite Laser may be useful for effective treatment of intractable melasma and PIH with fewer adverse events in dark Asian skin.

Background The prognostic value of CD30 expression in cutaneous extranodal natural killer/T‐cell lymphoma is controversial. Methods Clinicopathological features, survival outcomes, and prognostic implications of CD30 were retrospectively analyzed in 55 patients with cutaneous extranodal natural killer/T‐cell lymphoma. We classified patients into (i) primary cutaneous extranodal natural killer/T‐cell lymphoma and (ii) cutaneous extranodal natural killer/T‐cell lymphoma secondary to nasal disease depending on the primary tumor site. Results CD30+ cutaneous extranodal natural killer/T‐cell lymphoma was more common in patients with cutaneous extranodal natural killer/T‐cell lymphoma secondary to nasal disease than in those with primary cutaneous disease. CD30+ cases were more likely to present nodular lesions or cellulitis‐like swelling than CD30− cases. Histologically, CD30+ cutaneous extranodal natural killer/T‐cell lymphoma predominantly comprised large tumor cells compared with CD30− cases. However, the clinical morphology and tumor cell size were not associated with survival outcomes. CD30 expression was associated with better survival outcomes in patients with cutaneous extranodal natural killer/T‐cell lymphoma secondary to nasal disease. Conclusion CD30+ cutaneous extranodal natural killer/T‐cell lymphoma presented peculiar clinicopathological features and had more favorable disease course in patients with cutaneous dissemination from nasal disease.