Dermoscopy for the Pediatric Dermatologist Part I: Dermoscopy of Pediatric Infectious and Inflammatory Skin Lesions and Hair Disorders

The dermoscope allows physicians to examine the macroscopic and microscopic primary morphology of skin lesions, identify subtle clinical clues, confirm naked‐eye clinical diagnoses, and monitor treatment progress while posing little threat to the young patient. This review summarizes important dermoscopic structures seen in infectious and inflammatory skin conditions and hair disorders in children. Scabies, pediculosis, phthiriasis, molluscum contagiosum, tinea nigra, and verrucae are well characterized dermoscopically by delta‐shaped structures, ovoid‐shaped nits, the crab louse, red corona, brown strands or spicules, and multiple densely packed papilla with a central black dot surrounded by a whitish halo, respectively. These dermoscopic structures will be discussed, focusing on the dermoscopic morphologies and dermoscopic sensitivity for diagnosis and its utility in monitoring treatment progress. Dermoscopy has also been shown to significantly improve the clinician's diagnostic and monitoring accuracy of inflammatory skin lesions such as psoriasis, which is characterized dermoscopically by uniformly distributed dotted blood vessels, and lichen planus, which is characterized by whitish lines on a purple to reddish background. Dermoscopy of the hair and scalp (trichoscopy) facilitates the differential diagnosis of hair diseases in children, including alopecia areata, trichotillomania, and tinea capitis. It can also assist in the diagnosis of multiple genetic hair shaft disorders, such as monilethrix, trichorrhexis invaginata, trichorrhexis nodosa, pili torti, and pili annulati.     

[Translated article] Subungual Melanocytic Lesions in Pediatric Patients

The study of subungual melanocytic lesions can present challenges because of the clinical and histologic characteristics of the nail unit and the difficulty of performing nail biopsies and processing specimens. These lesions can be even more challenging in children due to differences in clinical and epidemiological profiles between the adult and pediatric populations. Many of the clinical features of subungual melanocytic lesions that would raise alarm in an adult do not have the same implications in children. Consensus is also lacking on when a nail biopsy is needed to rule out malignancy in the pediatric setting. In view of these considerations and the rarity of subungual melanoma in childhood, the recommended approach in most cases is a watch-and-wait strategy. Subungual melanocytic lesions in children may also show atypical histopathologic features that are not necessarily associated with aggressive behavior. Subungual melanoma is very rare in childhood, with just 21 cases described to date. None of the patients developed visceral metastasis or died as a result and the diagnosis was controversial in many of the cases. Considering the above and the significantly higher frequency and particular characteristics of longitudinal melanonychia with a benign etiology in children, subungual melanocytic lesions should be managed differently in this setting than in adults. In most cases, a watch-and-wait approach is the most appropriate strategy.     

皮肤镜在色素性皮损中的应用

皮肤镜是一种非侵袭性的在体诊断和鉴别诊断方法。它可以帮助临床医生评价许多肉眼无法看到的形态学特征和提高对色素性皮损的诊断。近年,皮肤镜的应用范围不断扩大,并出现了一些新术语和技术改进。对皮肤镜常用参数,尤其是在特殊解剖部位的应用,以及为简化诊断而形成的多种皮肤镜诊断标准和在随访及自动诊断中的作用进行评价。     

Use of Transparent Film Dressing for Dermoscopy of Mucosal Lesions

Genital and mucosal nevi are not uncommonly encountered in children. These type of nevi highlight challenges in performing a thorough dermoscopic examination. Contact dermoscopy can provide additional information about a nevus that non‐contact dermoscopy cannot. We propose applying a sterile transparent film dressing over the dermatoscope to act as a waterproof barrier that is also impermeable to bacteria and viruses. This provides a sanitary way to evaluate nevi in genital skin as well as on other mucosal surfaces.     

Laminin‐5 Expression in Melanocytic Lesions of the Skin

Background: Laminin‐5 is a basement membrane constituent that functions as an anchoring filament to integrin‐derived hemidesmosomes, and has been detected at the invasive front (tumor‐stromal interface) in many types of carcinomas. Our goal was to analyze laminin‐5 expression in melanocytic lesions and evaluate its role in tumor progression. Design: Immunohistochemical staining for laminin‐5 was performed on 101 cutaneous melanocytic lesions including 41 nevi, 31 primary melanomas, and 29 metastatic melanomas. A standard immunoperoxidase technique (ABC) was used with DAB chromagen and a primary monoclonal antibody to the laminin‐5 gamma2 chain (clone D4B5, 1:50, Chemicon International, Temecula, CA). Any degree of staining in melanoma cells or at the tumor‐stromal interface was considered positive. Results: Positive staining for laminin‐5 was observed in three of the primary melanomas (10.7%), three of the metastatic melanomas (10.3%), and none of the nevi. In primary melanomas, staining was observed predominately at the tumor‐stromal interface. In metastatic lesions, staining was observed around individual melanoma cells and melanoma cell nests.Conclusion: Expression of laminin‐5 was detected in a small percentage of primary and metastatic melanomas and in none of the nevi studied. Laminin‐5 expression does not appear to be essential for the development of melanomas or their metastases.     

HTERT Expression in Melanocytic Lesions: An Immunohistochemical Study on Paraffin‐Embedded Tissues

Progressive mucinous histiocytosis is a rare, benign, non‐Langerhans cell histiocytosis limited to the skin. A total of ten cases, all women, in four families, and one sporadic case have been described in the English literature. The disorder usually begins in childhood and progresses slowly. We report two sporadic cases of adult‐onset progressive mucinous histiocytosis in unrelated African American women, age 48 and 55 years old respectively, who developed red‐brown and flesh‐colored, asymptomatic papules on the face, arms and legs without truncal, mucosal or visceral involvement. The lesions show no spontaneous regression. Both patients lack associated systemic symptoms including polyuria, polydipsia or seizures. There is no underlying hyperlipidemia, paraproteinemia or lymphoproliferative disease. No family history of similar lesions can be identified. Light microscopy reveals dermal proliferation of spindle‐shaped histiocytes with abundant mucin deposition. Electron microscopy demonstrates a high number of myelin‐figures or zebra bodies in the cytoplasm of histiocytes. On immunohistochemistry, positive staining with macrophage markers CD68, HAM56 and lysozyme, and Factor XIIIa, a transglutaminase present in dermal dendrocytes, and negative staining with Langerhans cell markers CD1a and S100, and CD34, a marker present in dermal dendritic cells derived from uncommitted mesenchymal cells, are observed.