Onychophagia-induced longitudinal melanonychia

An otherwise-healthy 13-year-old girl with previously normal nails developed longitudinal pigmented bands on multiple fingernails. Physical examination revealed faintly pigmented bands on multiple fingernails and on the left fifth toenail. We believed that the cause of the pigmented bands was onychophagia-induced longitudinal melanonychia, a rare phenomenon, which emphasizes the need for dermatologists to question patients with melanonychia about their nail biting habits because they may not be forthcoming with this information.     

Frictional longitudinal melanonychia: a new entity

Longitudinal melanonychia of the toes initiated by repeated trauma from the footwear is described as a new entity in a clinical study of 12 patients. Its proper recognition should help to rule out the brown streaks due to malignant melanoma. The nail pigmentation appears over the distal bony phalanx where the deep matrix covered by the proximal nail fold is exposed to friction or pressure of the narrowing portion of the tip of the shoe. Histological studies revealed hyperplasia of the matrix, some melanin granules in the upper dermis with increased pigmentation of the basal cell layer of the epithelium, and marked melanotic pigment in the nail plate.     

Immunohistochemical study of 40 cases of longitudinal melanonychia

The etiology of longitudinal melanonychia (LM) is difficult to establish by clinical and dermoscopic examinations alone. Microscopic examination of the nail matrix remains crucial. Two groups of LM may be identified: melanocytic activation (melanic pigmentation of the matrix epithelium without any increase in the density of melanocytes) and melanocytic proliferation (lentigo, nevus, or melanoma). The histological examination is challenging, and immunohistochemical investigations can be helpful. The objective of this study was to analyze the immunohistochemical findings with routinely used markers in melanocytic tumors-S-100 protein, HMB-45, and Melan-A-in LM. A series of 40 cases were analyzed: 10 activations, 4 lentigines, 7 nevi, 12 in situ melanomas, and 7 invasive melanomas. The sensitivity of S-100 protein is weak in benign and malignant intraepithelial melanocytes of the nail matrix, and if this marker is performed alone, it may be wrongly reassuring. However, the use of S-100 protein is essential to differentiate invasive melanoma, lacking an intraepithelial component, and particularly desmoplastic melanoma, from epithelial and mesenchymal tumors. HMB-45 and Melan-A are more sensitive than S-100 protein for the evaluation of intraepithelial melanocytic proliferation of the nail apparatus, with HMB-45 being the most intense marker. In the dermal component, HMB-45 and Melan-A were less sensitive than S-100 protein. In conclusion, we recommend that the panel of antibodies used for histological evaluation of LM should include HMB-45 and/or Melan-A and S-100 protein only if an invasive melanoma is suspected.     

A case of adult-onset longitudinal melanonychia due to nail matrix compound nevus

A case of adult-onset longitudinal melanonychia caused by a compound nevus is described. Longitudinal melanonychias are mainly caused by melanocytic activation (hypermelanosis), lentigo (benign melanocytic hyperplasia), nevus, and melanoma. Nevi are more commonly seen in children than adults; however, melanocytic activation, atypical melanocytic proliferation, and melanoma are more frequent in adults. The majority of nail matrix nevi causing longitudinal melanonychia first appear in childhood and are junctional. Rarely, compound nevi are reported to cause longitudinal melanonychia in childhood.     

儿童纵行黑甲皮肤镜模式分析

目的了解儿童纵行黑甲的皮肤镜特点,探索通过皮肤镜模式分析诊断儿童纵行黑甲的方法。方法收集2013年6月—2015年9月就诊于首都医科大学附属北京儿童医院皮肤科的50例纵行黑甲患儿,分析其术前皮肤镜模式,对其中42例患儿行手术治疗,分析其术中皮肤镜模式。结果术前皮肤镜检查为灰色模式的8例患儿,均未行手术治疗,行手术治疗的42例患儿,术前甲板皮肤镜显示棕色条带的4例术中皮肤镜为棕色模式,组织病理证实为雀斑样痣。术前皮肤镜显示黑色条带的7例,术中表现为规则的棕色模式伴有色素球及色素斑,组织病理证实为甲母痣。术前显示规律的棕色线条组成的条带18例,术中皮肤镜为规则的棕色模式伴有色素球14例,规则棕色模式4例,组织病理分别证实为甲母痣和雀斑样痣。术前显示规律的棕色线条组成的条带伴色素球13例,术中皮肤镜为规则的棕色模式伴有色素球,组织病理证实其中12例为甲母痣,1例为黑素细胞活化。结论术前及术中皮肤镜检查及模式分析对儿童纵行黑甲的诊断具有显著意义。     

儿童纵行黑甲的临床和病理分析

目的:分析儿童纵行带状黑甲的临床和病理特点.方法:回顾性分析42例住院进行甲下黑斑切除术的3个月～12岁患儿的临床资料,并进行术后随访.结果:42例患儿中,3岁以内发病31例.病理示痣细胞者30例,只有色素颗粒而无痣细胞者12例.结论:儿童纵行黑甲多数发生于3岁以前,以良性黑素细胞增殖最多见.     

亚急性皮肤型红斑狼疮伴纵行黑甲一例

患者,男,35岁。因躯干、四肢红斑、丘疹8个月于2015年5月20日就诊我科。8个月前患者无明显诱因躯干、四肢出现肿胀性红斑、花生米大红色丘疹、结节,部分皮疹排列成环形,伴瘙痒。皮疹以前胸及上肢为重,半月内可消退,但反复新发,于日晒及饮酒后加重。曾反复就诊于当地医院,服抗组胺药治疗,病情无明显改善。     

Fungal melanonychia

Fungal melanonychia is a relatively rare nail disorder caused by nail infection that produces brown-to-black pigmentation of the nail unit. The number of organisms implicated as etiologic agents of fungal melanonychia is increasing, and the list currently tops 21 species of dematiaceous fungi and at least 8 species of nondematiaceous fungi. These superficial infections may clinically mimic subungual melanoma and are often not responsive to traditional antifungal therapy. This article reviews the literature on fungal melanonychia and the role of fungal melanin in infection.