This month's news from across the specialty
What's hot
December 1, 2019
In this monthly column, members of Dermatology World's Editorial Advisory Workgroup identify exciting news from across the specialty.
X marks the spot — PRAME expression for marking melanoma.
PRAME (PReferentially expressed Antigen in MElanoma) is a gene that was found to be associated with recognition of melanoma cell lines by cytotoxic T lymphocytes in the 90s. Recently, the expression of PRAME mRNA and protein have been tested by molecular and histologic assays respectively to assist with the identification of melanoma. Ferris et al (J Invest Dermatol. 2019; 139: 1127-34) have measured PRAME mRNA expression as part of a molecular panel collected by taping of pigmented lesions to differentiate early and superficial melanoma from benign nevi and nonmelanocytic lesions. As a screening tool to decrease excisional biopsies, the absence of PRAME expression in lesional tapings was associated with the absence of melanoma associated hotspot mutations (BRAF non-V600E, NRAS, and TERT) in 82% of 44 samples with histopathologic diagnoses. Lezcano et al (Am J Surg Pathol. 2018; 42(11): 1456–65) histologically evaluated PRAME expression in a wider variety of melanomas from MIS to metastatic. 87% of metastatic lesions were found to stain diffusely. The application of PRAME for differentiation of benign from malignant lesions and for melanoma margin assessment continues our march toward highly sensitive and specific genetic tools.
As we continue to search for the marker that is common to all melanomas and not seen in normal melanocytes, PRAME does show promise in combination with a panel of markers to continue to improve our genetic and histologic identification of melanoma. Certain classifications of melanoma, such as desmoplastic, are known to lose the histologic markers for melanocytes. Further studies will be important to identify the classifications of melanoma that lack the genetic and histologic markers for melanoma. Characterizing the genetically ambiguous melanomas that do not stain will strengthen the indications of these evolving tools for biopsy screening and tumor margin assessment.
It remains unclear what to recommend when diagnosing longitudinal melanonychia (LM). Even with second opinions from colleagues, it feels like the blind leading the blind, given limitations of the clinical exam. Nail matrix histopathologic examination remains the gold standard in diagnosis. Concerns regarding surgery and scar potential can result in disastrous consequences if a diagnosis of melanoma is delayed or missed.
I was thus excited upon reading the largest case series to date evaluating the modified shave surgery combined with nail window technique (J Am Acad Dermatol. 2019; 81:717-22). Sixty-seven patients with LM underwent this technique from 2015-2018 at the Department of Dermatology of the First Affiliated Hospital with Nanjing Medical University. In this procedure, the pigmented nail plate was cut with a CO2 laser (2mm margin used), and then removed, exposing the pigmented nail bed and matrix. Thermal damage to the underlying nail bed and matrix was avoided, as only several seconds were required to make this cut. The pigmented lesion was then exposed after making two lateral incisions and reflecting the proximal nail fold. Shave excision was then performed with a No. 15 scalpel blade to yield a specimen that was less than 0.5mm thick. Any pigmented lesion extending onto the nail bed was removed with the matrix lesion as a single specimen. The ventral surface of the removed nail plate was scraped to decrease the potential of melanocyte replantation before the nail plate was used as a biological dressing.
Compared to other invasive techniques such as punch or excisional biopsy that require excessive physical force to expose the pigmented nail matrix and a deeper specimen, 75% of patients remarkably had no scar using this technique. The recurrence rate was low at 13.3% as well. We now have another tool in our armamentarium when dealing with LM.
E-cigarettes have been the center of significant and concerning news given the increasing number of pulmonary problems that have been seen recently surrounding vaping. E-cigarettes, introduced in the early 2000s as a “safer” alternative to traditional cigarettes, have rapidly increased in usage and popularity, especially among the young. A whole generation of e-cigarette users has been established. The e-cigarette includes a juice or vape that is often flavored. This is heated by a coil and then cooled and inhaled. There is no long-term safety data on these substances. However, the FDA and CDC are currently investigating the recent increase in reports of severe respiratory illnesses in young patients and, therefore, calls for a ban are increasing. Although much less serious than the numerous recent reports of significant pulmonary damage found in those who are vaping, adverse side effects of e-cigarettes are not limited to the lungs and can also include cutaneous findings. It has become a new source of nickel allergy for some with reactions to the e-cigarette on the face and hands. Given the extensive number of vaping juices including hundreds of flavorings, and other potential allergens such as propylene glycol, plant materials and cannabis, dermatologists should inquire about vaping when evaluating patients with potential facial or hand dermatitis and consider the possibility of allergic contact dermatitis.
High-intensity focused electromagnetic (HIFEM) has recently been cleared by the FDA as an energy device approved to reduce fat and firm, strengthen, and build muscle mass. It is a non-invasive ambulatory procedure that delivers magnetic impulses into the tissue where it stimulates the underlying musculature. It is based on the application of rapidly changing magnetic fields that generate electrical currents and depolarize motor neurons causing sustained contractions of the targeted muscle. If the frequency of the stimulation is higher than the time needed for muscle relaxation, the muscle is forced into tetanic contraction, which is a highly stressful condition triggering changes in muscles as an adaptation to this stimulus. It is currently indicated for rectus abdominis muscle definition and gluteus maximus elevation. The device is applied to the selected targeted area for 30 minutes for four sequential treatments spaced at two-day intervals within a two-week period. The output intensity was kept just below the patient’s pain tolerance threshold in order to maintain maximum contraction throughout the treatment. The application of HIFEM induces non-voluntary extensive supramaximal muscle contractions and the muscle is forced to adapt to the load leading to hypertrophy and hyperplasia.
Studies showed that abdominal fat thickness was reduced on average by 18.6%, abdominal mass increased on average by 15.4%, an average of reduction in diastasis recti separation of 10.4% and waist circumference decreased by 1.4 inches (doi: 0.1097/DSS.0000000000001902). With the same treatment protocol, the gluteus maximus muscle showed an approximately 10.59% muscle hypertrophy which corresponded to a visible buttock lifting. At one year, photodocumentation was verified using MRI and CT assisted quantification (J Aesthet Reconstr Surg. 2019; 5(1):2). In vivo studies in a porcine model showed adipocyte apoptosis and muscle metabolism. Additionally, muscle mass increased by 23.44%, average area per single muscle fiber increased by 16.4% and the average number of muscle fibers increased by 7% which indicates muscle fiber hyperplasia. To date, no adverse events have been reported and as reflected by high GAIS ratings, there is a great deal of patient satisfaction. These preliminary results are promising and show a statistically positive trend in the criteria that was measured. Long term, greater than one-year follow up and robust scientific scrutiny will add further statistically significant measurements. An additional muscular anatomic area, the arm (brachialis and triceps muscles), has recently been added as an indication for this technology and future research will hopefully substantiate the initial clinical findings. This new technology is unique in the aesthetic arena and is not intended to replace diet and exercise, but rather the repetitive frequency of these voluntary contractions is to enhance muscle definition.
