Kaposi Sarcoma of the Nail Unit: A Case Report and Review of the Literature.

Introduction: Kaposi sarcoma is an angioproliferative neoplasm. Its manifestations are well known but nail involvement seems extremely underreported. Case Presentation: A 55-year-old man presented with a 6-month history of a growing subungual tumor affecting the third right toe. After surgical excision, histological examination revealed a Kaposi sarcoma. Discussion: We report a case of Kaposi sarcoma with nail involvement of only one toe as the first and unique manifestation, which is exceptional.

Genome Analysis of Triploid Hybrid Leishmania Parasite from the Neotropics.

We discovered a hybrid Leishmania parasite in Costa Rica that is genetically similar to hybrids from Panama. Genome analyses demonstrated the hybrid is triploid and identified L. braziliensis and L. guyanensis-related strains as parents. Our findings highlight the existence of poorly sampled Leishmania (Viannia) variants infectious to humans.

A clinicopathological description of COVID-19-induced chilblains (COVID-toes) correlated with a published literature review.

BACKGROUND: The abundance of publications of COVID-19-induced chilblains has resulted in a confusing situation. METHODS: This is a prospective single-institution study from 15 March to 13 May 2020. Thirty-two patients received PCR nasopharyngeal swabs. Of these, 28 patients had a thoracic CT-scan, 31 patients had blood and urine examinations, 24 patients had skin biopsies including immunohistochemical and direct immunofluorescence studies, and four patients had electron microscopy. RESULTS: COVID-19-induced chilblains are clinically and histopathologically identical to chilblains from other causes. Although intravascular thrombi are sometimes observed, no patient had a systemic coagulopathy or severe clinical course. The exhaustive clinical, radiological, and laboratory work-up in this study ruled-out other primary and secondary causes. Electron microscopy revealed rare, probable viral particles whose core and spikes measured from 120 to 133 nm within endothelium and eccrine glands in two cases. CONCLUSION: This study provides further clinicopathologic evidence of COVID-19-related chilblains. Negative PCR and antibody tests do not rule-out infection. Chilblains represent a good prognosis, occurring later in the disease course. No systemic coagulopathy was identified in any patient. Patients presenting with acral lesions should be isolated, and chilblains should be distinguished from thrombotic lesions (livedo racemosa, retiform purpura, or ischemic acral necrosis).

In vivo assessment of optical properties of basal cell carcinoma and differentiation of BCC subtypes by high-definition optical coherence tomography.

High-definition optical coherence tomography (HD-OCT) features of basal cell carcinoma (BCC) have recently been defined. We assessed in vivo optical properties (IV-OP) of BCC, by HD-OCT. Moreover their critical values for BCC subtype differentiation were determined. The technique of semi-log plot whereby an exponential function becomes linear has been implemented on HD-OCT signals. The relative attenuation factor (µraf ) at different skin layers could be assessed.. IV-OP of superficial BCC with high diagnostic accuracy (DA) and high negative predictive values (NPV) were (i) decreased µraf in lower part of epidermis and (ii) increased epidermal thickness (E-T). IV-OP of nodular BCC with good to high DA and NPV were (i) less negative µraf in papillary dermis compared to normal adjacent skin and (ii) significantly decreased E-T and papillary dermal thickness (PD-T). In infiltrative BCC (i) high µraf in reticular dermis compared to normal adjacent skin and (ii) presence of peaks and falls in reticular dermis had good DA and high NPV. HD-OCT seems to enable the combination of in vivo morphological analysis of cellular and 3-D micro-architectural structures with IV-OP analysis of BCC. This permits BCC sub-differentiation with higher accuracy than in vivo HD-OCT analysis of morphology alone.

Validation of a diagnostic algorithm for the discrimination of actinic keratosis from normal skin and squamous cell carcinoma by means of high-definition optical coherence tomography.

Actinic keratoses (AKs) commonly arise on sun-damaged skin. Visible lesions are often associated with subclinical lesions on surrounding skin, giving rise to field cancerization. To avoid multiple biopsies to diagnose subclinical/early invasive lesions, there is an increasing interest in non-invasive diagnostic tools, such as high-definition optical coherence tomography (HD-OCT). We previously developed a HD-OCT-based diagnostic algorithm for the discrimination of AK from squamous cell carcinoma (SCC) and normal skin. The aim of this study was to test the applicability of HD-OCT for non-invasive discrimination of AK from SCC and normal skin using this algorithm. Three-dimensional (3D) HD-OCT images of histopathologically proven AKs and SCCs and images of normal skin were collected. All images were shown in a random sequence to three independent observers with different experience in HD-OCT, blinded to the clinical and histopathological data and with different experience with HD-OCT. Observers classified each image as AK, SCC or normal skin based on the diagnostic algorithm. A total of 106 (38 AKs, 16 SCCs and 52 normal skin sites) HD-OCT images from 71 patients were included. Sensitivity and specificity for the most experienced observer were 81.6% and 92.6% for AK diagnosis and 93.8% and 98.9% for SCC diagnosis. A moderate interobserver agreement was demonstrated. HD-OCT represents a promising technology for the non-invasive diagnosis of AKs. Thanks to its high potential in discriminating SCC from AK, HD-OCT could be used as a relevant tool for second-level examination, increasing diagnostic confidence and sparing patients unnecessary excisions.