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.

New tools in nail disorders.

Tumors of the nail unit may be difficult to diagnose because of the screening effect of the nail plate. In longitudinal melanonychia, several new promising techniques assist with early diagnosis of melanoma (in vivo matrix dermoscopy and immunohistochemistry) as well as sparing as much of the healthy tissues as is possible (shave biopsy technique). Diagnosing nail disorders is in some instances difficult both for the clinician and the pathologist. New tools such as polymerase chain reaction have been proposed for onychomycosis, which accounts for more than half of nail conditions, will allow quick and accurate diagnosis. However, polymerase chain reaction analysis remains expensive and is not routinely used by clinicians. Scoring nail dystrophy by clinical observation remains very subjective; therefore, severity indexes have been proposed. Another emerging noninvasive technique is forensic analysis of nail clippings for detection of drug intake and abuse, as well as exposure to environmental pollution.

Onychomycosis: beyond cosmetic distress.

Onychomycosis, or fungal infection of the nail, is the most common nail disease affecting children (although to a lesser extent) as well as adults. The distress it provokes is not only of a cosmetic kind; it may impair the quality of life. The different clinical types of onychomycosis should be differentiated from similar-looking nail diseases. As far as therapy is concerned, the appearance of new antifungal drugs in the 1990s makes our job easier, but it does not allow us to cure 100% of the patients. Relapses still exist. The aim of this article is to help dermatologists achieve a tailor-made treatment for their patients. The clinical type, the compulsory mycological investigations, the age of the patient, his medical history (drug intake), as well as the use of nail cosmetics, must be considered.

Pigmented nail disorders.

Nail pigmentation is defined by the presence of melanin in the nail plate. It most frequently has the appearance of a longitudinal pigmented band, called longitudinal mel-anonychia (LM). LM is an important aspect of ungual pathology because it can be the first sign of nail apparatus melanoma. The aim of this article is to help distinguish those types of melanonychia that are worrisome and should lead to biopsy from those that are reasonably reassuring and need only be followed clinically. Histology, differential diagnosis, and biopsy techniques also are considered.

Tinea capitis in Brussels: epidemiology and new management strategy.

BACKGROUND: We found pre-established directives inadequate to cope with the current increase in anthropophilic tinea capitis in Brussels. OBJECTIVES: To study new epidemiological profiles and to define new strategies for management and prevention. PATIENTS AND METHODS: A total of 122 children affected by tinea capitis were followed in our department from October 1, 2001, until September 30, 2002. The results were assessed retrospectively. RESULTS: Anthropophilic tinea capitis represented 89.34% of the cases. The implicated anthropophilic dermatophytes were by decreasing frequency: Microsporum langeronii (39.34%), Trichophyton soudanense (28.69%), Trichophyton violaceum (18.03%) and Trichophyton tonsurans (3.28%). CONCLUSION: The responsible pathogens reflect immigration flows originating mostly from Black and North Africa. Precise recommendations for each visit are detailed.