Selective Cryolysis of Melanocytes: Critical Temperature and Exposure Time to Induce Selective Pigmentary Loss in Yucatan Pig Skin.

BACKGROUND AND OBJECTIVES: Cryotherapy for melanocytic lesions is often accompanied by collateral damage to the surrounding skin, resulting in skin necrosis and scarring. Adipocytes, like melanocytes, are neural crest-derived cells. Adipocytes have been shown to be more sensitive to cold exposure than their neighboring cells of ectodermal origin, such as epidermal keratinocytes. Such differential sensitivity to cold exposure has led to the development of novel treatment modalities, like cryolipolysis, to selectively target a cell type while sparing neighboring cells. STUDY DESIGN/MATERIALS AND METHODS: In this study, we investigated the roles of controlled skin freezing, tissue temperature, and exposure time in inducing selective loss of melanocytes and skin depigmentation in swines. RESULTS: The results of our study demonstrated that contact cooling of the skin surface causes selective loss of epidermal melanocytes when the tissue temperature reaches -7.5°C or cooler with an exposure time of 10 minutes or longer, leading to partial skin depigmentation in swine skin. Longer exposures combined with colder temperature exposure led to more complete depigmentation in the treated skin surface. CONCLUSION: Cold-sensitivity of melanocytes can be harnessed to selectively remove melanocytes while sparing surrounding keratinocytes. The results from this study demonstrated that improved clinical treatments specifically targeting melanocytic lesions is possible using skin cooling to achieve tissue temperatures capable of inducing selective loss of melanocytes without skin necrosis or scarring. Additional studies are needed to optimize the treatment conditions to prolong the selective removal of melanocytes. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Lidocaine-induced potentiation of thermal damage in skin and carcinoma cells.

OBJECTIVE: Lidocaine acts as a local anesthetic by blocking transmembrane sodium channel permeability, but also induces the synthesis of heat shock proteins and sensitizes cells to hyperthermia. A previous study reported two cases of deep focal skin ulceration at points corresponding to depot local lidocaine injection sites after treatment with non-ablative fractional resurfacing and it was hypothesized that lidocaine had focally sensitized keratinocytes to the thermal damage of laser treatment. The objective of this study was to investigate whether lidocaine potentiates hyperthermia damage to both normal and cancerous skin cells using an in vitro model. METHODS: Normal skin cell lines (fibroblasts, keratinocytes), skin cancer cell lines (melanoma, basal cell carcinoma), and a mucosal cancer cell line (cervical carcinoma) were exposed to various concentrations of lidocaine (0-0.3%) with or without hyperthermia (37°C, 42°C). RESULTS: Compared to normal skin cells, we demonstrate that cancer cell lines show significantly increased cell toxicity when a moderate temperature (42°C) and low lidocaine concentrations (0.1-0.2%) are combined. The toxicity directly correlates with a higher percentage of cells in S-phase (28-57%) in the cancer cell lines compared to normal skin cell lines (13-19%; R-square 0.6752). CONCLUSION: These results suggest that lidocaine potentiates thermal sensitivity of cell cycle active skin cells. The direct correlation between cell toxicity and S-phase cells could be harnessed to selectively treat skin and mucosal cancer cells while sparing the surrounding normal tissue. Additional research pre-clinically and clinically using several different heat sources (e.g., lasers, ultrasound, etc.) and lidocaine concentrations is needed to confirm and optimize these results. Lidocaine-enhanced hyperthermia may provide a non-invasive, alterative treatment option for highly proliferating, superficial skin, and mucosal lesions such as cancer or warts. Lasers Surg. Med. 51:88-94, 2019. © 2018 Wiley Periodicals, Inc.

Airborne particulate concentration during laser hair removal: A comparison between cold sapphire with aqueous gel and cryogen skin cooling.

BACKGROUND: High concentrations of sub-micron nanoparticles have been shown to be released during laser hair removal (LHR) procedures. These emissions pose a potential biohazard to healthcare workers that have prolonged exposure to LHR plume. OBJECTIVE: We sought to demonstrate that cold sapphire skin cooling done in contact mode might suppress plume dispersion during LHR. METHODS: A total of 11 patients were recruited for laser hair removal. They were treated on the legs and axilla with a 755 or 1064 nm millisecond-domain laser equipped with either (i) cryogen spray (CSC); (ii) refrigerated air (RA); or (iii) contact cooling with sapphire (CC). Concentration of ultrafine nanoparticles <1 µm were measured just before and during LHR with the three respective cooling methods. RESULTS: For contact cooling (CC), counts remained at baseline levels, below 3,500 parts per cubic centimeter (ppc) for all treatments. In contrast, the CSC system produced large levels of plume, peaking at times to over 400,000 ppc. The CA cooled system produced intermediate levels of plume, about 35,000 ppc (or about 10× baseline). CONCLUSIONS: Cold Sapphire Skin cooling with gel suppresses plume during laser hair removal, potentially eliminating the need for smoke evacuators, custom ventilation systems, and respirators during LHR. Lasers Surg. Med. 50:280-283, 2018. © 2017 Wiley Periodicals, Inc.

Occupational exposures and determinants of ultrafine particle concentrations during laser hair removal procedures.

BACKGROUND: Occupational exposures to ultrafine particles in the plume generated during laser hair removal procedures, the most commonly performed light based cosmetic procedure, have not been thoroughly characterized. Acute and chronic exposures to ambient ultrafine particles have been associated with a number of negative respiratory and cardiovascular health effects. Thus, the aim of this study was to measure airborne concentrations of particles in a diameter size range of 10 nm to 1 µm in procedure rooms during laser hair removal procedures. METHODS: TSI Model 3007 Condensation Particle Counters were used to quantify the particle count concentrations in the waiting and procedure rooms of a dermatology office. Particle concentrations were sampled before, during, and after laser hair removal procedures, and characteristics of each procedure were noted by the performing dermatologist. RESULTS: Twelve procedures were sampled over 4 days. Mean ultrafine particle concentrations in the waiting and procedure rooms were 14,957.4 particles/cm3 and 22,916.8 particles/cm3 (p < 0.0001), respectively. Compared to background ultrafine particle concentrations before the procedure, the mean concentration in the procedure room was 2.89 times greater during the procedure (p = 0.009) and 2.09 times greater after the procedure (p = 0.007). Duration of procedure (p = 0.006), body part (p = 0.013), and the use of pre-laser lotion/type of laser (p = 0.039), were the most important predictors of ultrafine particle concentrations. Use of a smoke evacuator (a recommended form of local exhaust ventilation) positioned at 30.5 cm from the source, as opposed to the recommended 1-2 in., lowered particle concentrations, but was not a statistically significant predictor (p = 0.49). CONCLUSIONS: Laser hair removal procedures can generate high exposures to ultrafine particles for dermatologists and other individuals performing laser hair removal, with exposure varying based on multiple determinants.

Ultraviolet-fluorescent tattoo location of cutaneous biopsy site.

BACKGROUND: Cutaneous biopsies often heal with little or no scarring. Prior studies have shown an alarming percentage of patients who incorrectly identify biopsy sites at the time of surgery. OBJECTIVE: To investigate the safety and utility of an ultraviolet (UV)-fluorescent tattoo for biopsy site identification. MATERIALS AND METHODS: A preclinical proof of concept was established with skin culture. An UV-fluorescent tattoo was applied to discarded neonatal foreskin in culture medium. The stability of the tattooed skin was examined clinically and histologically. One patient with a recurrent basal cell carcinoma in a difficult-to-identify location underwent tattoo application at the time of biopsy to demarcate the site. The patient was monitored for tattoo reaction and referred for surgical excision. RESULTS: The cultured tissue exhibited stable UV fluorescence with daily washing. Tissue histology demonstrated tattoo particles lining the skin edge under fluorescent microscopy. The patient was reluctant to undergo another surgical procedure and instead returned to our clinic at 3 months and 17 months after the biopsy for management of other tumors. The patient had no symptoms of allergic reaction to the tattoo dye. The fluorescent tattoo remains invisible under visible light and visible only under Wood's light. CONCLUSION: The present study documents the utility of an UV-fluorescent tattoo to locate a biopsy site.

Incidence of invasive squamous cell carcinomas in biopsy-proven squamous cell carcinomas in situ sent for Mohs micrographic surgery.

BACKGROUND: Squamous cell carcinoma (SCC) in situ (SCCIS) is often treated without any pathologic confirmation of tumor clearance. It is unclear how often an invasive SCC is harbored within a lesion in which the initial biopsy demonstrated SCCIS because of inadequate sampling. This study examines the final histologic diagnosis of cases in which the initial biopsies were diagnosed as SCCIS and evaluates factors that may correlate with a histologic upstaging of the diagnosis. METHODS: We prospectively recruited 29 consecutive patients with biopsy-proven SCCIS sent for Mohs micrographic surgery (MMS). Each tumor underwent MMS, and the central blocks of the Mohs debulking specimens were horizontally sectioned at 30-µm intervals until exhausted. A fellowship-trained Mohs surgeon and a board-certified dermatopathologist processed and examined these sections to determine the final histologic diagnosis of the tumor. RESULTS: Of the 29 subjects with biopsy-proven SCCIS, nine were found to harbor invasive SCC on final histology. Of the remaining lesions, seven had residual SCCIS, whereas the rest exhibited only actinic keratoses or scars. Approximately 31% of lesions showed evidence of invasive SCC. Correlating the clinical characteristics of the lesions with their corresponding final histologic diagnoses, the lesions harboring invasive SCC were more likely to demonstrate clinical signs of residual tumor (scales and papular changes) and be larger than 1.4 cm in diameter. LIMITATIONS: Our experience at a single institution in the northeastern United States may not be reflective of a wider population. There is also a possible referral bias, because only lesions with high clinical suspicion for invasive SCC were referred for MMS. CONCLUSION: Although biopsy-proven SCCIS is often treated with modalities that are best suited for superficial disease and do not involve a final pathologic confirmation of clearance (e.g., cryotherapy, electrodesiccation and curettage), this study demonstrated that up to 31% of biopsy-proven SCCIS lesions may harbor invasive SCC. Clinical signs of residual tumor and a diameter larger than 1.4 cm are statistically significant predictors of underlying invasive SCC. These data suggest that treatment modalities that include histologic control of tumor removal should also be strongly considered for the treatment of select biopsy-proven SCCIS meeting the above criteria.

Preoperative expectations and values of patients undergoing Mohs micrographic surgery.

BACKGROUND: Dermatologists have championed Mohs micrographic surgery (MMS) for its unsurpassed treatment success for skin cancers, safety profile, cost-effectiveness, and tissue-sparing quality. It is unclear whether patients undergoing MMS also value these characteristics. OBJECTIVE: To evaluate patients' preoperative expectations of MMS and identify the factors that may influence such expectations METHODS: The study prospectively recruited participants who were newly diagnosed with skin cancer and referred for MMS. A questionnaire listing the characteristics of MMS was given to the participants asking them to score the importance of each characteristic on a 10-point scale. The participants were also asked to provide information regarding their gender, age, subjective health status, education level, family annual income, and their referral source RESULTS: On average, participants placed the highest value, in descending order, on a treatment that yielded the highest cure rate, reconstruction initiation only after complete tumor removal, and the surgeon being a skin cancer specialist. Overall, participants placed high values on characteristics of MMS that dermatologists have long esteemed. CONCLUSION: Our data corroborate that MMS is a valuable procedure that meets the expectations not just of physicians, but also of patients. The authors have indicated no significant interest with commercial supporters.

Cross-Linked Fluorescent Supramolecular Nanoparticles as Finite Tattoo Pigments with Controllable Intradermal Retention Times.

Tattooing has been utilized by the medical community for precisely demarcating anatomic landmarks. This practice is especially important for identifying biopsy sites of nonmelanoma skin cancer (NMSC) due to the long interval (i.e., up to 3 months) between the initial diagnostic biopsy and surgical treatment. Commercially available tattoo pigments possess several issues, which include causing poor cosmesis, being mistaken for a melanocytic lesion, requiring additional removal procedures when no longer desired, and potentially inducing inflammatory responses. The ideal tattoo pigment for labeling of skin biopsy sites for NMSC requires (i) invisibility under ambient light, (ii) fluorescence under a selective light source, (iii) a finite intradermal retention time (ca. 3 months), and (iv) biocompatibility. Herein, we introduce cross-linked fluorescent supramolecular nanoparticles (c-FSNPs) as a "finite tattoo" pigment, with optimized photophysical properties and intradermal retention time to achieve successful in vivo finite tattooing. Fluorescent supramolecular nanoparticles encapsulate a fluorescent conjugated polymer, poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene] (MPS-PPV), into a core via a supramolecular synthetic approach. FSNPs which possess fluorescent properties superior to those of the free MPS-PPV are obtained through a combinatorial screening process. Covalent cross-linking of FSNPs results in micrometer-sized c-FSNPs, which exhibit a size-dependent intradermal retention. The 1456 nm sized c-FSNPs display an ideal intradermal retention time (ca. 3 months) for NMSC lesion labeling, as observed in an in vivo tattoo study. In addition, the c-FSNPs induce undetectable inflammatory responses after tattooing. We believe that the c-FSNPs can serve as a "finite tattoo" pigment to label potential malignant NMSC lesions.

Gaseous and Particulate Content of Laser Hair Removal Plume.

Importance: Potentially harmful chemicals are released when tissues are vaporized. Laser hair removal (LHR) causes heating and often vaporization of hairs, producing both a signature malodorous plume and visible particulates. Objective: To characterize the chemical composition and quantify the ultrafine particle content of the plume generated during LHR. Design, Setting, and Participants: In the laser center of a large academic hospital, discarded terminal hairs from the trunk and extremities were collected from 2 adult volunteers. The hair samples were sealed in glass gas chromatography chambers and treated with a laser. The laser plume was analyzed by gas chromatography-mass spectrometry (GC-MS). During LHR treatment, two 6-L negative pressure canisters were used to capture 30 seconds of laser plume, and a portable condensation particle counter was used to measure ultrafine particulates (<1 µm). Ultrafine particle concentrations were measured within the treatment room, within the waiting room, and outside the building. Main Outcomes and Measures: The chemical content of the laser plume was analyzed with GC-MS and screened for aerosolized toxins using Environmental Protection Agency-certified methods. The ambient concentration of ultrafine particles during LHR was measured by condensation particle counters. Results: Analysis with GC-MS identified 377 chemical compounds. Sixty-two of these compounds, of which 13 are known or suspected carcinogens and more than 20 are known environmental toxins, exhibited strong absorption peaks. During LHR, the portable condensation particle counters documented an 8-fold increase compared with the ambient room baseline level of ultrafine particle concentrations (ambient room baseline, 15 300 particles per cubic centimeter [ppc]; LHR with smoke evacuator, 129 376 ppc), even when a smoke evacuator was in close proximity (5.0 cm) to the procedure site. When the smoke evacuator was turned off for 30 seconds, there was a more than 26-fold increase in particulate count compared with ambient baseline levels (ambient baseline, 15 300 ppc; LHR without smoke evacuator for 30 seconds, 435 888 ppc). Conclusions and Relevance: These findings establish the concern that the burning-hair plume often present during LHR should be considered a biohazard, warranting the use of smoke evacuators, good ventilation, and respiratory protection, especially for health care workers with prolonged exposure to LHR plume.

Germline fumarate hydratase mutations and evidence for a founder mutation underlying multiple cutaneous and uterine leiomyomata.

Multiple cutaneous and uterine leiomyomata syndrome (MCL) is an autosomal dominant disease characterized by the presence of concurrent benign tumors of smooth muscle origin (leiomyoma) in the skin and uterus of affected females, and in the skin of affected males. MCL can also be associated with type II papillary renal cell cancer (HLRCC). The genetic locus for MCL and HLRCC was recently mapped to chromosome 1q42.3-43 and subsequently, dominantly inherited mutations in the fumarate hydratase gene ( FH ) were identified. Importantly, analysis of the FH gene in tumors of MCL patients revealed a second mutation inactivating the wild-type allele in some tumors. Based on these findings, it has been suggested that FH may function as a tumor suppressor gene in MCL. Here, we report the analysis of the FH gene in a group of 11 MCL families, with the identification of 8 different mutations accounting for the disease in all families. One of the mutations, 905-1G>A, has been identified in 4 families of Iranian origin. The analysis of highly polymorphic markers in the vicinity of the FH gene showed a shared haplotype in these 4 families, suggesting that 905-1G>A represents a founder mutation. Collectively, identification of 5 novel and 3 recurrent mutations further supports the role of FH in the pathogenesis of MCL.

Germline fumarate hydratase mutations in families with multiple cutaneous and uterine leiomyomata.

Germline mutations in the fumarate hydratase gene (FH) predispose to multiple cutaneous and uterine leiomyoma syndrome (MCL) and MCL associated with renal cell cancer. MCL is inherited in an autosomal dominant pattern, manifesting as skin leiomyoma and uterine fibroids in affected individuals. Fumarate hydratase, a component of the tricarboxylic acid cycle, acts as a tumor suppressor gene in the development of cutaneous and uterine leiomyoma and renal cell cancer in this syndrome. Here we report the clinical and mutational analysis of five families with MCL, with the identification of five new mutations affecting highly conserved residues of the FH protein. These results provide further evidence for the role of the FH gene in the pathogenesis of MCL.