Nail cosmetology.

Nail cosmetics is enjoying growing success due to recent technological advances. Manicures can be responsible for mechanical, infectious or allergic adverse effects. Nail cosmetics (e.g., nail varnishes, acrylic false nails, light-curing gels, and adhesive false nails) incorporate substances that harden after solvent evaporation or after polymerization. Allergic reactions can occur, remotely with conventional varnishes and locally with polymerizing substances. Artificial nails incur a risk of carrying infectious agents which can cause serious infection, and should not be used by caregivers. Recently, there has been a worrisome increase in the frequency of acrylate allergy, due to the appearance of home kits and lack of information in the general public. The infectious, allergic and toxic risks incurred by consumers and professionals regarding manicure or pedicure treatments and the application of nail cosmetics are the subject of recommendations and monitoring measures.

Three atypical/malignant onychopapillomas in a 52-case series with immunohistochemical study.

BACKGROUND: Onychopapilloma (OP) is a benign tumor of the nail. Haneke reported one case of malignant OP in 2021. No systematic immunohistochemistry study has been conducted on OP. The aim of our study was to identify possible malignant OP in our series of OP and to describe the immunohistochemical expression of p16, p53, and Ki67 in typical and atypical/malignant ones. METHODS: Ninety-one cases were available for pathological review. Immunohistochemical analysis could be performed on 52 cases. RESULTS: In 88 of 91 cases, the diagnosis of OP was confirmed. Three atypical/malignant cases were observed. No OP expressed p16. A normal p53 expression was observed in two thirds of the cases, an abnormal increased p53 expression in one third, including the three atypical cases. A normal Ki67 expression was observed in 84% of the cases, an abnormal Ki67 expression with focal heterogeneous expression in the suprabasal layers in 6% and in all suprabasal cell layers in 10%, including the three atypical cases. CONCLUSIONS: The diagnosis of atypical/malignant OP may be underestimated. The expression of Ki67 and p53 in these tumors differs from the expression observed in conventional OP. The absence of p16 expression confirms that human papillomavirus does not play a role in the etiopathogenesis of OP.

Adenomatoid tumor of the skin: Differential diagnosis of an umbilical erythematous plaque.

Adenomatoid tumors are benign tumors of mesothelial origin that are usually encountered in the genital tract. Although they have been observed in other organs, the skin appears to be a very rare location, with only one case reported in the literature to our knowledge. We report a second case of an adenomatoid tumor, arising in the umbilicus of a 44-year-old woman. The patient presented with an 8-month-old erythematous and firm plaque under the umbilicus. A skin biopsy showed numerous microcystic spaces dissecting a fibrous stroma and lined by flattened to cuboidal cells with focal intraluminal papillary formation. This little-known diagnosis constitutes a diagnostic pitfall for dermatopathologists and dermatologists, and could be misdiagnosed as other benign or malignant entities. Through this case report, a practical approach and diagnostic keys have been devised to avoid misdiagnosis and overtreatment.

Direct examination, histopathology and fungal culture for the diagnosis of onychomycosis: A retrospective, comparative study on 2245 specimens.

BACKGROUND: Onychomycosis affects 5.5% of the general population and represents up to 50% of all nail diseases. Diagnosis and pathogen identification are essential in order to plan an adequate treatment. Many diagnostic techniques are available, and however, no solid data regarding comparison between different techniques over a large number of specimens are available to date. OBJECTIVES: To compare sensitivity and specificity of direct examination, histopathology and fungal culture in our referral mycology laboratory. METHODS: Nail specimens received at the cutaneous pathology and mycology laboratory of the University Hospital Saint-Pierre (Brussels, Belgium) between 1 January and 15 May 2018 were retrospectively analysed. All specimens were submitted to direct examination and culture. In cases of adequate specimen size, histopathology was performed. Fungal culture was considered the gold standard for diagnosis. RESULTS: A total of 2245 nail samples were included in the study. Onychomycosis was diagnosed in 1266 specimens. Sensitivity and positive predictive value were found to be higher for direct examination compared to histopathology, while sensitivity of direct examination was found to be lower. Combined approach with all the three techniques showed the highest rate of positivity, followed by the association of direct examination and histopathology. CONCLUSIONS: To our knowledge, this study included the largest number of nail specimens to date, allowing a comparison between direct examination, culture and histopathology. Direct examination showed to be the most performing technique in routine practice. Histopathology represents the most effective option in cases where both specimen size and laboratory resources are adequate. Our paper adds to the literature the 'real-life' experience of the mycology laboratory of a referral centre for nail diseases.

Nail Unit Blue Nevi: A 11-Case Series and Review of the Literature.

BACKGROUND: Blue nevus of the nail apparatus is a rare entity and only isolated cases are reported in the literature. OBJECTIVE: The aim of this study was to better characterize blue nevus at the nail unit. METHODS: Retrospective analysis of all nail unit blue nevi from the Nail Group of the French Society of Dermatology was compared to the literature. RESULTS: Eleven cases were retrieved from 2002 to 2019 with an average age of 45 years. The majority were women (9/11) and acquired (10/11). Hands were more frequently involved (9/11) with a predilection for the thumb and 2 cases were located on the hallux. Nail unit blue nevus mostly presented as a well-delimited blue spot of the lunula (9/11) and histologically was of the common type (10/11). There was no malignancy. CONCLUSION: Nail unit blue nevus is a rare asymptomatic benign entity, mostly acquired on the thumb or the hallux of women. The most frequent presentation is a painless blue spot on the lunula. Congenital blue nevi seem to only affect the paronychium. Main differential diagnosis is melanoma and histopathological examination is mandatory.

Chilblains.

Idiopathic chilblain is a relatively common yet poorly recognized acrosyndrome. This literature review aims to better understand and draw attention to this disorder. Chilblain is a localized inflammation of the skin that occurs on exposure to cold but non-freezing wet weather. It usually resolves spontaneously. The etiology is uncertain, but vasospasm seems to play a role in this abnormal reaction to cold. Diagnosis is most often based on clinical presentation, but a skin biopsy can be useful in dubious cases. In histology, dermal edema and an inflammatory infiltrate are usually present. A distribution of the infiltrate particularly around the eccrine gland is typical. Systemic symptoms and underlying autoimmune disease should be screened. Avoiding cold and keeping extremities warm is the first recommendation for management, as well as smoking cessation. Calcium channel blockers (in particular nifedipine) seems to be the treatment that has been most evaluated in chilblains. However, their effectiveness is not confirmed by all studies. Topical betamethasone is often used but its effect has not been confirmed by randomized clinical trials. Other treatments, such as pentoxifylline, hydrochloroquine and topical nitroglycerin have shown positive effects only in a reduced number of patients. Acupuncture seems to bring a benefit.

Immunohistochemical characterization of benign activation of junctional melanocytes and melanoma in situ of the nail unit.

BACKGROUND: Immunohistochemical (IHC) stains that distinguish benign, pigmented nail lesions from malignancy are needed. Candidate markers of malignant transformation include p16, HMB45, and Ki-67, with p16 being of particular interest. There is limited knowledge about the spectrum of p16 expression in pigmented lesions, especially junctional melanocytic proliferations of the nail. The objective of this study was to determine if any of these markers demonstrate diagnostic utility in distinguishing between benign activation of junctional melanocytes (BAM) and melanoma in situ (MIS) of the nail unit. METHODS: In this retrospective study, ten cases of BAM and eight cases of MIS were identified. Archival slides available for review included H&E (hematoxylin and eosin), Fontana-Masson, and MelanA (Mart1) IHC slides. IHC studies for p16, HMB45, and dual-color Ki-67/MelanA (Mart1) were then performed. RESULTS: None of the tested IHC stains distinguished BAM from MIS. p16 IHC expression was uniformly negative with the exception of two cases of MIS. HMB45 was positive in all BAM and MIS cases. Ki-67/MelanA showed positive Ki-67 staining of MelanA-positive melanocytes in two cases of MIS, and all other cases of MIS and BAM were negative for Ki-67. The two positive p16 and two positive Ki-67/MelanA cases were non-overlapping. CONCLUSION: p16, HMB45, and Ki-67/MelanA IHC studies show no apparent utility in distinguishing BAM from MIS in the nail unit.

Subungual Solitary Angiokeratoma Simulating a Squamous Cell Carcinoma.

Subungual angiokeratoma is extremely rare. Only 1 case is reported in the literature, presenting as a longitudinal pigmented band on a toenail. We report a case of a subungual angiokeratoma on a fingernail of a 43-year-old woman, clinically mimicking a squamous cell carcinoma. Medical imaging revealed a soft tissue tumor and erosion of the distal phalanx. Although extremely rare, solitary angiokeratomas may arise in the nail apparatus and should be added to the differential diagnosis of subungual warty tumors.

Treatment of Ingrowing Toenails With Phenol 88% or Trichloroacetic Acid 100%: A Comparative, Prospective, Randomized, Double-Blind Study.

BACKGROUND: Phenol is the gold standard for chemical matricectomy in ingrowing toenail. Recently, trichloroacetic acid (TCA) was used as cauterant. Both agents have high success rates but a postoperative healing time claimed to be faster for TCA rather than phenol. OBJECTIVE: Comparing the efficacy, the postoperative oozing time, the inflammatory reaction, and the postoperative pain. MATERIALS AND METHODS: Comparative, prospective, randomized, double-blind study. Eighty-four patients with 96 ingrowing toenails were randomized in 2 groups. Forty-six ingrowing toenails were treated with phenol 88% and 50 with TCA 100% within a 4-month period. Patients were observed 4 times for the presence of oozing and for the degree of inflammation. Patients assessed also oozing and pain on a scale basis during 34 days. RESULTS: Oozing was observed to be less with phenol treatment, as from the second week. Inflammation was also significantly inferior in the phenol group at Week 4. Patients evaluated the incidence of pain below 2/10 for both cauterants, while oozing was higher with TCA during 34 days. The overall success rates of both groups were similar with 100%. CONCLUSION: Phenol and TCA are both effective but TCA does not offer any advantage in terms of postoperative morbidity compared with phenol.

An international survey about nail histology processing techniques.

BACKGROUND: There are limited data on nail histopathology techniques. The objective of this study was to examine nail histopathology techniques currently in use internationally. METHODS: An online survey was sent to the European Nail Society and Council for Nail Disorders during 2015-2016. RESULTS: There were 57 respondents, from twenty countries comprising dermatologists, podiatrists and pathologists. Specimens were unmarked or marked using ink or a suture and fixed in 10% formalin, from 6 to 48 hours before embedding in paraffin wax (90% [17/19]), liquid nitrogen (frozen section, 1/19) and 2-hydroxyethylmethacrylate (plastic, 1/19). Nail softening was undertaken by 71% (17/24) of respondents for 6 to 48 hours using Mollifex Gurr (12.5%, 3/24), 10% potassium hydroxide solution (12.5%, 3/24) or 10% potassium thioglycolate cream (12.5%, 3/24). Section thickness was 4 to 9 µm (62.5%), using a steel microtome (92%,12/13) on glass slides (91.6%, 11/12). Hematoxylin and eosin (H&E) was routine for all biopsies and Periodic acid Schiff (PAS) for fungus. The favored stain for differentiating melanin and hemoglobin was Fontana-Masson (60%, 6/10). For pigmented lesions, Melan-A was always employed by all respondents (9/9). CONCLUSION: Nail histopathology processing has some small variations from normal skin processing.

Pseudoangiomatous xanthelasmoid mastocytosis: two case reports showing the hypervascularity of this rare variant of cutaneous mastocytosis.

Xanthelasmoid mastocytosis or xanthelasmoidea is a rare clinical variant of cutaneous mastocytosis characterized by a yellow hue of the clinical lesions, which are often misdiagnosed as juvenile xanthogranuloma. We present two pediatric cases of xanthelasmoid mastocytosis presenting as isolated mastocytomas, which are notable histopathologically for their hypervascularity. This pseudoangiomatous variant of cutaneous mastocytosis is important for pathologists to have knowledge of, so that a diagnosis of a vascular tumor is not rendered accidentally. The yellow hue has previously been explained by the usual deep and solid dermal mast cell infiltrate. In the two presented cases, however, the mast cell infiltrate was sparse, and the yellow color cannot be related to infiltrate density. We believe that the hypervascularity is at least one factor in the production of clinical xanthelasmoid appearance, and we propose the term 'pseudoangiomatous xanthelasmoid mastocytosis' to properly describe this rare variant of cutaneous mastocytosis.

Diagnosis using nail matrix.

Diagnosing nail matrix diseases requires knowledge of the nail matrix function and anatomy. This allows recognition of the clinical manifestations and assessment of potential surgical risk. Nail signs depend on the location within the matrix (proximal or distal) and the intensity, duration, and extent of the insult. Proximal matrix involvement includes nail surface irregularities (longitudinal lines, transverse lines, roughness of the nail surface, pitting, and superficial brittleness), whereas distal matrix insult induces longitudinal or transverse chromonychia. Clinical signs are described and their main causes are listed to enable readers to diagnose matrix disease from the nail's clinical features.

Macular arteritis associated with concurrent HIV and hepatitis B infections: a case report and evidence for a disease spectrum association with cutaneous polyarteritis nodosa.

We report the first case of macular arteritis in a 33-year-old Black, African female with concurrent human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infections. Of particular interest in macular arteritis is the striking discordance between the clinical presentation and the histopathological findings, a fact that both dermatologists and dermatopathologists should be aware. Histopathologically, the case showed typical findings of macular arteritis with a perivascular, predominantly lymphocytic, infiltrate and intraluminal thrombosis. Both HIV and HBV have been reported as viral inducers of cutaneous polyarteritis nodosa (PAN). Their association with macular arteritis in this case supports existing evidence that macular arteritis and cutaneous PAN represent a single-disease spectrum of vasculitides, with macular arteritis representing the chronic, lymphocytic and indolent stage, and cutaneous PAN the neutrophilic, acute stage with a risk for systemic progression. Lymphocytic thrombophilic arteritis (LTA), a third, uncommon disease would be in between macular arteritis and cutaneous PAN on a spectrum. Features of this case and other published cases provide strong evidence that there is a single, mild-to-severe disease spectrum of macular arteritis-LTA-cutaneous PAN.