Subungual melanoma with blue naevus-like morphological features: a clinicopathological retrospective analysis of nine cases

Melanocytic lesions in the nail apparatus are often challenging. Both subungual melanomas (SUM) and blue naevus of the nail are very rare. Occasionally, melanomas may mimic blue naevus histologically. Benign and malignant blue melanocytic lesions are commonly associated with G protein mutations, a distinct abnormality not associated with conventional subungual melanomas. We describe the clinical, histological and immunohistochemical features of nine cases of SUM with blue naevus-like morphological features. Mutations in exon 4 and 5 of GNAQ and GNA11 were investigated in two cases, which showed no mutations. RNA-seq of one case revealed unknown mutations along with mutations in ATM, METK and ARID1A. Our study delineates a variant of SUM that mimics blue naevus. Awareness of this pitfall is important when evaluating heavily pigmented lesions around the nail in order to avoid misdiagnosis. Appropriate sampling of subungual lesions and clinicopathological correlation are paramount to reach the correct diagnosis.

Retrospective analysis of nail biopsies performed using the Medicare Provider Utilization and Payment Database 2012 to 2017

Subungual melanoma (SUM) is subset of acral melanoma that develops within the nail unit and is associated with a poor prognosis. Nail biopsy is the only way to definitively diagnosis SUM. Our objectives were to analyze the Medicare database for nail biopsy utilization and to compare the annual nail biopsy rate with the estimated incidence of SUM in the United States. A retrospective study on nail biopsy data was performed using the Medicare Provider Utilization and Payment Database 2012 to 2017. The number of nail biopsies performed per 100 000 people was compared to SUM incidence per 100 000 people. Podiatrists, dermatologists, other physicians, and NP/PAs respectively performed 12.12, 0.42, 0.08, 0.07 nail biopsies per 100 000 people annually. Dermatologists performed adequate nail biopsies to cover the minimum (0.7%), but not the maximum (3.5%) estimated incidence of SUM. Only 0.28% and 1.01% of general dermatologists and Mohs surgeons, respectively, performed nail biopsies in 19/50 (38.00%) states and 69/929 (7.42%) zip codes. Limitations of our study were that nail biopsies on patients less than 65 years, and those with no or commercial health insurance were not analyzed. In sum, very few dermatologists performed nail biopsies in the Medicare database. Increased efforts are needed to educate dermatologists on nail surgery.

Clinicomycological and Histopathological Profile of Onychomycosis: A Cross-sectional Study from South India

Background

Onychomycosis (OM) is a fungal infection of the finger or toenails caused by dermatophytes, yeasts, or nondermatophyte molds (NDMs) and can involve any component of the nail unit. OM, apart from being asymptomatic, is a chronic disease and warrants long-term treatment.

Aims

The aim was to study the clinicoepidemiological features of OM and to evaluate the mycological and histopathological features among patients attending the dermatology outpatient department.

Subjects and Methods

A cross-sectional hospital-based study was performed in 500 patients with symptoms related to the nails and nail folds. OM was confirmed in 284 patients by potassium hydroxide (KOH) mount, fungal culture, or biopsy. Descriptive analysis of the data was undertaken.

Results

The study included 284 confirmed cases of OM of which 117 (41.1%) were positive for fungal elements by KOH mount, 168 (59.1%) samples showed positivity in fungal culture, and 62 (21.8%) samples had positive nail biopsy results. Distolateral subungual OM was the most common clinical type (47.6%). Among the fungal isolates, a predominance of dermatophytes was observed followed by yeasts and NDMs. The most common dermatophytic fungal isolate in the culture was Trichophyton rubrum (45%).

Conclusion

Our study implies the importance of laboratory diagnosis of OM as it can mimic diverse nail disorders. As the role of NDMs and yeasts is on the rise for etiology of OM, investigations such as KOH examination, culture, or nail biopsy becomes essential for correct diagnosis and management.

Novel uses of skin biopsy punches in dermatosurgery

The skin punch or surgical punch is an instrument which is used almost exclusively by dermatologists. It is a circular hollow blade attached to a pencil-like handle ranging in size from 0.5 to 10 mm. It is available as a disposable, reusable, and automated instrument. The punch can be used as a diagnostic, therapeutic, and cosmetic tool in dermatology. We have used punch as a diagnostic, therapeutic, and cosmetic tool in our dermatosurgery practice in our hospital. Various original research articles, text book publications, and review articles were studied and compiled. Techniques used by various authors and our own experiences with punch have been described. This article aims at providing the novel usefulness of skin biopsy punch in dermatology as the basic punch surgery is quick and easy to learn. Complications such as bleeding and infection are minimal.

Case of acrodermatitis continua of Hallopeau following psoriasis with atypical clinical presentation

We present a 63-year-old Japanese woman who had clinically unique symmetrical skin rashes on her lower face, inframammary area, back and extremities, with some pustules on the cheeks. Skin biopsy specimens showed typical findings of psoriasis, and Psoriasis Area and Severity Index score was 5.9. After the skin lesions were treated successfully with vitamin D3 ointment, pustules developed on the tips of the fingers and toes, with paronychial and subungual involvement. The pathology of the nail matrix was consistent with pustular psoriasis, and the patient was diagnosed with acrodermatitis continua of Hallopeau (ACH) following psoriasis with an unusual clinical presentation. ACH was well controlled with a low dose of cyclosporin. Our patient is a rare case chronologically affected by two diseases in the same category. We confirmed that ACH is a variant of pustular psoriasis, and believe that the patient could provide another clue to determining the entity of ACH.

Nail psoriasis: the journey so far

Nail involvement is an extremely common feature of psoriasis and affects approximately 10-78% of psoriasis patients with 5-10% of patients having isolated nail psoriasis. However, it is often an overlooked feature in the management of nail psoriasis, despite the significant burden it places on the patients as a result of functional impairment of manual dexterity, pain, and psychological stress. Affected nail plates often thicken and crumble, and because they are very visible, patients tend to avoid normal day-to-day activities and social interactions. Importantly, 70-80% of patients with psoriatic arthritis have nail psoriasis. In this overview, we review the clinical manifestations of psoriasis affecting the nails, the common differential diagnosis of nail psoriasis, Nail Psoriasis Severity Index and the various diagnostic aids for diagnosing nail psoriasis especially, the cases with isolated nail involvement. We have also discussed the available treatment options, including the topical, physical, systemic, and biological modalities, in great detail in order to equip the present day dermatologist in dealing with a big clinical challenge, that is, management of nail psoriasis.

Morphopathological aspects of healthy nails and nails affected by onychomycosis

Patients of onychomycosis are common in the dermatology practice. Contemporary morphology creates opportunities to study the functional units of the nail when such infections occur from morphopathological point of view. There were 22 nails biopsies from onychomycosis patients taken for the research of morphopathological changes in the thickened nail plate affected by onychomycosis. Samples of cadaverous' nails were used as a control material. The material was stained with haematoxylin and eosin and immunohistochemical methods. Terminal deoxynucleotidyl transferase dUTP nick end labelling reaction and periodic acid-Schiff reaction were also performed. We found patchy hypertrophy in the granulose layer of the epidermis, with focal acanthosis. In the horn layer, we identified nests of parakeratosis of various sizes, with incorporations of homogenous and eosinophil masses. We found high levels of interleukin 6 and interleukin 10 positive cells in the nail bed and in the bloodstream. Interleukin 1, however, was not a part of any of the functional units of any of the nails. Significant amount of fibres containing human beta defensin-2 were found in the bed and plate of the nail. Therefore one can conclude that as regards the nails affected by onychomycosis, the most effective morphopathogenical processes include cytokine and defensin excretion occurrence in the nail bed.