Recurrence rate of oral melanotic macule treated with Q-switched alexandrite laser versus surgical excision: a retrospective cohort study / 口腔疾病防治

Objective@#To compare the recurrence rates between 755 nm Q-switched alexandrite laser (QSAL) treatment and surgical excision of oral melanotic macules (OMM).@*Methods@#This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. A retrospective cohort study was designed to collect demographic and clinical characteristics and follow-up data from patients with OMM. Patients who received QSAL or surgical excision in the Department of Oral Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine from January 2019 to August 2021 were included. The one-year recurrence rate was investigated as the primary outcome. Long-term adverse reaction rates were investigated as safety indicators. Kaplan-Meier analyses were performed to analyze the recurrence-free rates between the groups.@*Results@#A total of 57 patients were enrolled in this study. 16 patients underwent surgical excision, and 41 underwent QSAL. The baseline demographic and clinical characteristics between the groups were not significantly different. No recurrence (0%) of OMM was observed in the surgical excision group, while in the QSAL group, the macule recurred in 12 patients (29.27%). The average duration of recurrence was 6.08 months after treatment. Recurrence was not found to be associated with smoking (P = 1.000), gastrointestinal polyps (P = 1.000), longitudinal melanonychia (P = 0.187), family history (P = 0.552), treatment sessions (P = 0.567) or multiple macule lesions (P = 0.497). Compared with treatment with surgical excision, the odds ratio of recurrence for treatment with QSAL was 4.41, with a 95% confidence interval of 1.27-15.24 (P = 0.020). In the surgical excision group, 3 patients (18.75%) reported depressions and scars on the lesion, while no long-term adverse reactions (0%) were reported in the QSAL group (P = 0.019).@*Conclusion@#Compared with surgical excision, the advantage of QSAL is the low long-term adverse reaction rate, while the disadvantage is the relatively high one-year recurrence rate. It is necessary to communicate the advantages and disadvantages of the two methods with OMM patients to assist in clinical decision-making.

Efficacy of Q-switched Alexandrite laser on the nevus of Ota / 中华医学美学美容杂志

Objective To observe the clinical efficacy of Q-switched Alexandrite laser at 752 nm in the treatment of nevus of Ota. Methods A total of 1985 cases of nevus of Ota were treated with the Q-switched Alexandrite laser PhotoGenica HT10, and then the ages, frequency of treatment and interval of treatment were analyzed. Results The excellent effective rate was 97.88 %, and the total effective rate was 100 % in 1985 cases. Most patients in all age group received the excellent effects, however, there was no significant difference between the groups. Most patients acheived the excellent effect after 4 to 5 treatments, and very few patients (0.8 %) needed over 10 treatments; the rate ofpatient who needed 1-3 treatments or 6-10 treatments was 18. 2 % and 25.8 %, respectively. The patients had the most excellent efficacy in the group that the interval of two treatments was 4 to 6months, however, there was no significant difference between the group of the interval of two treatments over 6 months. In our study, there were only a few cases (4.48 %) with slight side reaction,such as temporary pigmentation and hypopigmentation and scar. Conclusions 752 nm Q-switched Alexandrite laser is one of effective and safe treatments for nevus of Ota.

Histopathologic, Immunohistochemical, and Electron Microscopic Findings of Pigmented Skin Lesions Immediately after Q-switched Alexandrite Laser Treatment / 대한피부과학회지

BACKGROUND: There have been only a few electron microscopic studies after laser treatment of pigmented skin lesions. OBJECTIVE: The purpose was to investigate the pathologic, immunohistochemical, and electron microscopic changes following Q-switched alexandrite laser treatment of pigmented skin lesions. METHODS: Three patients with acquired bilateral nevus of Ota-like macules, and 2 patients with cafeau lait macule were irradiated with Q-switched alexandrite laser. Forty biopsies were taken before and immediately after laser treatment. Hematoxylin-eosin, Fontana-Masson, and gp100 staining were performed for the evaluation of the histopathologic and immunohistochemical findings of the specimens. Electron microscopic findings were also evaluated. RESULTS: Histopathologically, suprabasilar separations were observed immediately after laser treatment. Vacuolar alterations of pigment-containing cells were frequently found in the epidermis and/or in the dermis. Fontana-Masson and gp100 staining positivity changed to negative or decreased in the epidermis immediately after laser treatment, while they changed to negative in the dermis. Ultrastructurally, epidermal pigment-containing cells frequently showed severe vacuolar changes in the cytoplasm, pyknotic nuclei, and vacuolated and/or fragmented melanosomes immediately after laser treatment. Dermal melanocytes frequently revealed vacuolated and/or fragmented melanosomes immediately after laser treatment. CONCLUSION: Histopathologic, immunohistochemical, and electron microscopic examination of pigmented skin lesions immediately after Q-switched alexandrite laser treatment demonstrated vacuolated or fragmented melanosomes and vacuolar alteration of pigment-containing cells in the epidermis and/or in the dermis, which suggested selective photothermolysis of melanosomes.

The Removal of Eyebrow Tattoos by the Q-switched Alexandrite Laser / 대한피부과학회지

BACKGROUND: Women sometimes have eyebrows tattooed for cosmetic purpose. But until recently, the removal of tattoos has been difficult. Several laser techniques have been proposed for the removal of tattoos. The lasers that have been used most successfully are the Q-switched systems because of their ability to target tattoo pigment selectively with minimal risk of adverse tissue response. OBJECTIVE: The objective of this study was to determine the clinical effectiveness of the newest Q-switched system, the alexandrite laser, in removing both eyebrow tattoos and to observe side effects such as scarring or permanent pigmentary changes. METHODS: Forty seven patients with both eyebrows tattooed were treated with the Q-switched alexandrite laser (755 nm, 100 ns) at eight week intervals and clinically evaluated.

Successful Treatment of Mucosal Melanosis of the Lip with Q-switched Alexandrite Laser / 대한피부과학회지

Mucosal melanosis such as labial and vulvar pigmented macules is common as well as cosmetically disfiguring benign pigmented lesions. Until the recent development of laser treatments, it was impossible to remove a mucosal melanosis without leaving a scar. The Q-switched Alexandrite laser, which has a wavelength of 755 nm and a short pulse duration of 100 nanoseconds, has been used for the treatment of dermal pigmentary disorders such as Nevus of Ota and tattoos. We treated two patients with labial melanosis by the Q-switched Alexandrite laser using a 2,4 mm spot size and energy fluences of 4.5 to 7 J/cm2. Their mucosal pigmentations were completely cleared without adverse sequelae or recurrence after one session of the treatment. We report that Q-switched Alexandrite laser might be a highly effective and safe modality for the treatment of mucosal melanosis and suggest it as the treatment of choice.

A Case of Ota's Nevus Treated by Combination Therapy with Cryosurgery and the Q-Switched Alexandrit Laser / 대한피부과학회지

Ota's nevus is a mongolian spot-like macular blue-black or gray-brown patchy pigmentation that most commonly occurs unilaterally in areas innervated by the first and second division of the trigeminal nerve. We report a case of Ota's nevus treated by combination therapy with cryosurgery and a Q-switched Alexandrite laser. A 48-year-old female had had a type III Ota's nevus from birth. Cryosurgery was tried at first using hard chalk dry ice on the lesion of the forehead and cheek. After that, The Q-switched Alexandrite laser was used three times at twelve week intervals at the site of the eyelid. Good therapeutic effects were gained and our patient was very satisfied. There were no complications or scarring. A Biopsy of the area treated revealed a similar histological pattern with significantly less melanin indicating melanin removal. Combination therapy with cryosurgery and an Alexandrite laser on the Ota's nevus may be cheaper, more effective and a safer method. It may also reduce the limitation of the two methods when used individually.

The Effect of the Alexandrite Laser for The Removal of Tattoos / 대한피부과학회지

BACKGROUND: Until the recent development of the Q-switched lasers, it was impossible to remove tattoos without causing scarring and sometimes disfiguring. Variations in wavelengths and pulse widths may result in different clinical effects or risks. OBJECTIVE: The purpose of this study was to investigate the therapeutic effects of the alexandrite laser in removing tattoos clinically, histologically and ultrastructually. METHODS: Fourty-two patients with gray, black, and blue-black colored tattoos were treated with fluences ranging from 6.5 to 8.0 J/cm2 at a minimal interval of 6 weeks. We took pictures of each tattoo prior to treatment and each treatment session in order to evaluate clinical irnprovement. Biopsy specimens were obtained from 8 patients, on prearranged times: before, immediately after, one week after and 6 weeks after irradiation. RESULTS: The results if the treatment of 42 patients with tattoos were analyzed. After two treatment sessions, 89% of patients showed 51% to 95% improvement. Transient hyperpigmentation and hypopigmentation occurred in 7 patients. However, skin atrophy, hypertrophic scar or infection did not occur. Ir a biopsy specimen taken 6 weeks after irradiation on light microscopy, most of tattoo granules disappeared without collagen fiber change. However, macrophage engulfing tattoo granules and a minute amount of tattoo granules still remained in the dermis on electron microscopy. CONCLUSION: The .alexandrite laser is considered to be a safe and effective treatment rnodality for removal of gray, black, and blue-black tattoo pigments.