Onychocytic Matricoma Presenting as Longitudinal Melanonychia in a Skin of Color Patient.

Introduction: Onychocytic matricoma (OCM) is a benign acanthoma of the nail matrix that presents with longitudinal melanonychia and nail thickening. Only 18 previously reported cases of OCM are in the literature since it was first described in 2012. Case Presentation: The purpose of this case report was to report a unique presentation of OCM in the toenail of a Black patient as well as to review the clinical presentation, histologic features, and management of this rare entity. Previously described cases presented on the fingernails and were predominantly in white males. Conclusion: OCM is a benign entity that may mimic a nail unit melanoma or squamous cell carcinoma especially when pachyonychia is present. Despite some clinical clues to suggest a diagnosis of OCM, a nail matrix biopsy is often required to rule out malignancy.

Quality and Perceived Usefulness of Patient-Submitted Store-and-Forward Teledermatology Images.

Importance: Patient-submitted images vary considerably in quality and usefulness. Studies that characterize patient-submitted images in a real-life setting are lacking. Objective: To evaluate the quality and perceived usefulness of patient-submitted images as determined by dermatologists and characterize agreement of their responses. Design, Setting, and Participants: This survey study included patient images submitted to the Department of Dermatology at Duke University (Durham, North Carolina) between August 1, 2018, and December 31, 2019. From a total pool of 1200 images, 10 dermatologists evaluated 200 or 400 images each, with every image being evaluated by 3 dermatologists. Data analysis occurred during the year leading up to the article being written. Main Outcomes and Measures: The primary outcomes were the responses to 2 questions and were analyzed using frequency counts and interrater agreement (Fleiss κ) to assess image quality and perceived usefulness. We performed a random-effects logistic regression model to investigate factors associated with evaluators' decision-making comfort. We hypothesized that most images would be of low quality and perceived usefulness, and that interrater agreement would be poor. Results: A total of 259 of 2915 patient-submitted images (8.9%) did not depict a skin condition at all. The final analysis comprised 3600 unique image evaluations. Dermatologist evaluators indicated that 1985 images (55.1%) were useful for medical decision-making and 2239 (62.2%) were of sufficient quality. Interrater agreement for a given image's diagnostic categorization was fair to substantial (κ range, 0.36-0.64), while agreement on image quality (κ range, 0.35-0.47) and perceived usefulness (κ range, 0.29-0.38) were fair to moderate. Senior faculty had higher odds of feeling comfortable with medical decision-making than junior faculty (odds ratio [OR], 3.68; 95% CI, 2.9-4.66; P < .001) and residents (OR, 5.55; 95% CI, 4.38-7.04; P < .001). Images depicting wounds (OR, 1.75; 95% CI, 1.18-2.58; P = .01) compared with inflammatory skin conditions and that were in focus (OR, 5.56; 95% CI, 4.63-6.67; P < .001) had higher odds of being considered useful for decision-making. Conclusions and Relevance: In this survey study including 10 dermatologists, a slight majority of patient-submitted images were judged to be of adequate quality and perceived usefulness. Fair agreement between dermatologists was found regarding image quality and perceived usefulness, suggesting that store-and-forward teledermatology initiatives should consider a physician's individual experiences and comfort level. The study results suggest that images are most likely to be useful when they are in focus and reviewed by experienced attending physicians for wound surveillance, but dermatologists may be burdened by irrelevant or unsuitable images.

An Atypical Myelomonocytic Cell Infiltrate: Use of Next-Generation Sequencing to Diagnose Indeterminate Cell Histiocytosis.

ABSTRACT: Indeterminant cell histiocytosis (ICH) is a rare lymphoproliferative disorder that demonstrates features of Langerhans and non-Langerhans cell histiocytoses and diagnosis can be challenging. We present a case of a 62 year old woman with a generalized eruption of erythematous papules on the face, trunk and extremities. Skin biopsies demonstrated a dermal mononuclear cell infiltrate with monocytic (CD4, CD33), histiocytic (CD68, CD163), and dendritic cell (CD1a) immunophenotype but negative for Langerhans' cell marker (CD207). The differential diagnosis included leukemia cutis and ICH, and further workup revealed a normal bone marrow biopsy. To confirm the diagnosis of ICH, next generation sequencing with ETV3-NCOA2 gene fusion was performed and was positive. The patient's condition improved with methotrexate and narrow band UVB phototherapy. Our case adds to the existing literature supporting the use of next-generation sequencing to test for ETV3-NCOA2 gene fusion in suspected cases of ICH.

Clinical and direct immunofluorescence characteristics of cutaneous toxicity associated with enfortumab vedotin.

Enfortumab vedotin (EV), a novel antibody-drug conjugate approved for metastatic urothelial carcinoma, causes a variety of cutaneous adverse reactions. We present two cases of bullous eruptions following treatment with EV, both demonstrating IgG deposition on direct immunofluorescence (DIF) correlating to the location of nectin-4 in the epidermis. This suggests that the IgG component of EV binding to nectin-4 in keratinocytes is likely a primary contributor to the high rates of cutaneous toxicity.

Cryptococcus-like changes in the setting of vasculitis.

Cutaneous vasculitis has many underlying causes, and the clinical and histological findings often overlap. Inflammatory vasculitis can mimic infection; however, distinction is critical for the timely institution of appropriate therapy. We present two patients who had generalized polymorphous eruptions whose cutaneous pathology showed vasculitis with unusual haloed yeast-like cells within the inflammatory infiltrate, mimicking Cryptococcus. The unusual cells stained negatively with Gomori methenamine silver and periodic acid-Schiff fungal stains, but positively for CD68 and had cytoplasmic reactivity with antibody to myeloperoxidase (MPO). Both patients had positive serum anti-MPO antibodies. The first patient experienced a rapidly fatal course, whereas the second patient improved with prompt initiation of systemic corticosteroids. Interestingly, the second case had prior biopsy showing Sweet syndrome with crypotoccoid-appearing cells. Cryptococcoid cells have been described previously in association with neutrophilic dermatoses, but not in the setting of vasculitis as was seen in our patients. Our cases add to the existing literature on crypotoccoid mimickers, and are the first to be reported in association with vasculitis.