Margaret I. Sanchez

Nail damage from gel polish manicure

Manicures can result in nail damage via instrumentation, nail polish, nail polish removers, and artificial nails. We report nail weakness, brittleness, and thinning in five subjects after the application of a new manicure system called gel polish and removal with acetone and manual peeling. All subjects complained that the polish was very difficult to remove and that their nails became much thinner after the procedure. Pseudoleukonychia and onychoschizia lamellina were noted on examination. One subject underwent ultrasound and reflectance confocal microscopy (RCM) measurements of nail plate before and after the gel polish application, which showed thinned nail plate (0.063 vs. 0.050 cm and 0.059 vs. 0.030 cm, respectively). Overall, we call attention to the adverse effects of gel polish manicures in five subjects. In addition, our case illustrates potential utility of ultrasound and RCM in measuring nail plate thickness.

How, and from which cell sources, do nevi really develop?

Melanocytic neoplasms are a diverse group of benign and malignant tumors with variable clinical features. While some models still promote the epidermal melanocyte as the origin of melanocytic neoplasms, clinical findings are inconsistent with this theory for the majority of tumors. Despite advances in naevus and melanoma biology, the location and differentiation status of the cell of origin remains undefined. Germ line genetics, biological state and cellular location of the mutated cell, as well as local environmental factors all likely play a role in the development of melanocytic neoplasms. Herein, we will review potential models for melanocytic neoplasia and discuss research challenges and opportunities.

Intramedullary spinal cord metastases of melanoma.

Intramedullary spinal cord metastases (ISCMs) are extremely rare. An exact diagnosis may be difficult even when the primary tumour is known. Patients usually present with back pain and signs and symptoms of spinal cord compression, such as hemiparesis or hemisensory impairments. Magnetic resonance imaging (MRI) is considered to be the main diagnostic tool for intramedullary lesions as it is very sensitive, but non-specific, in distinguishing between ISCMs and primary cord tumours. Optimal treatment in patients with ISCMs remains controversial. We report a case of ISCMs of melanoma, with a review of the clinical and radiological characteristics of these medullary lesions and their prognosis, as well as the different therapeutic approaches.

Dark Homogeneous Streak Dermoscopic Pattern Correlating With Specific KIT Mutations in Melanoma

IMPORTANCE Mutations driving melanoma growth have diagnostic, prognostic, and therapeutic implications. Traditional classification systems do not correlate optimally with underlying melanoma growth-promoting mutations. Our objective was to determine whether unique dermoscopic growth patterns directly correlate with driving mutations. OBSERVATIONS We evaluated common driving mutations in 4 different dermoscopic patterns (rhomboidal, negative pigmented network, polygonal, and dark homogeneous streaks) of primary cutaneous melanomas; 3 melanomas per pattern were tested. Three of the 4 patterns lacked common mutations in BRAF, NRAS, KIT, GNAQ, and HRAS. One pattern, the dark homogeneous streaks pattern, had unique KIT mutations in the second catalytic domain of KIT in exon 17 for all 3 samples tested. Two tumors with the dark homogeneous streaks pattern turned out to be different primary melanomas from the same patient and had different sequence mutations but had an impact on the same KIT domain. CONCLUSIONS AND RELEVANCE While future study is required, these results have multiple implications. (1) The underlying melanoma-driving mutations may give rise to specific dermoscopic growth patterns, (2) BRAF/NRAS mutations in early melanomas may not be as common as previously thought, and (3) patients may be predisposed to developing specific driving mutations giving rise to melanomas or nevi of similar growth patterns.

Onychomatricoma has channel‐like structures on in vivo reflectance confocal microscopy

Onychomatricoma is a benign fibroepithelial nail matrix tumor that infiltrates the nail plate leading to multiple tunneled cavities lined with matrix epithelium and filled with serum. Diagnostic features of onychomatricoma on reflectance confocal microscopy (RCM) have not been previously described.

Nevogenesis: A Benign Metastatic Process?

It is generally accepted that cutaneous nevogenesis is a localized event that occurs exclusively in the dermis and/or epidermis. However, the discovery of nevocytes circulating in the peripheral blood suggests that other, more systemic, benign metastatic processes could also be involved. The theoretical role of lymphatic and hematogenous dissemination of loosely adherent, immature nevus progenitor cells in the development of nodal nevi and eruptive melanocytic nevi will be reviewed.

Melanomagenesis: multifaceted attacks on the genome

Jenna R. Bordelon, Margaret I. Sanchez and James M. Grichnik Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, USA; Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA; Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, FL, USA Correspondence: James M. Grichnik, MD, PhD, Anna Fund Melanoma Program Sylvester Comprehensive Cancer Center; Frankel Family Division of Melanocytic Tumors, Department of Dermatology; and Interdisciplinary Stem Cell Institute, Miller School of Medicine, University of Miami, 1501 NW 10th Ave, 9th Floor Biomedical Research Building, Room 912, Miami, FL 33136, USA, Tel.: (305) 243-6045, Fax: (305) 243-6072, e-mail: jgrichnik@med.miami.edu

Melanoma's high C>T mutation rate: is deamination playing a role?

The majority of melanoma mutations are C>T transitions, and most bear UV signatures. However, other process may contribute to the high C>T mutation rate. Okura et al., have demonstrated immunohistochemical evidence of deaminating enzymes, activation‐induced cytidine deaminase (AID) and apolipoprotein B mRNA‐editing enzyme catalytic polypeptide‐like 3B (APOBEC3B) in melanoma. Both have been implicated in cancer. While further validation is necessary, these findings warrant consideration of a role for deamination in melanomagenesis. Deamination primarily drives C>T transitions. Compared with trunk/extremity melanomas, acral melanomas display a significantly higher percentage of ‘spontaneous’ and ‘AID’ mutation signature events suggesting deamination may be particularly important in this subgroup.

Molecular Nevogenesis: An Update

Nevogenesis is a multifactorial process that involves a complex interplay of genetic and environmental factors. Growth promoting mutations (NRAS, HRAS, BRAF, and GNAQ) known to be present in various types of malignant melanoma have also been identified in benign nevi. Their presence roughly correlates with congenital, Spitz, acquired, and blue nevi, respectively. These mutations are likely to play a critical role in driving nevogenesis through activation of the MAP kinase pathway. However, mutations in these genes result in different cellular effects that cause the cells to migrate, proliferate, and differentiate to different extents within the skin. This causes each mutation to give rise to a characteristic growth pattern. Further research is necessary to fully understand nevus development given that most of the same developmental pathways are also present in melanoma.

Confocal Microscopy of Challenging Dermoscopic Diagnoses

D ERMOSCOPIC EVALUATION HAS BEEN shown to reduce unnecessary biopsies and to increase the accuracy of melanoma diagnosis. However, some lesions remain dermoscopically challenging, as in the 3 paired malignant and benign cases shown in the Figure: A and B reveal a disorganized reticular pattern and a moth-eaten border; C and D reveal structureless areas and areas of gray and asymmetrical dots; and E and F reveal a disorganized reticular pattern, structureless areas, and areas of gray and moth-eaten borders. Reflectance confocal microscopy provides additional information that can serve to facilitate the correct diagnosis. Please go to http://www.archdermatol.com to view the confocal features and diagnosis for each of these cases (eFigures). Confocal microscopy also reveals some lesion structural details that are not readily appreciated by standard histopathology. This is particularly evident for the extension of melanocytic dendrites and for the presence of retractile (presumably melanocytic) cells in the papillary dermis residing under some histologically diagnosed in situ melanomas.