Symmetric facial macules in an Asian woman.

Hori nevus, also known as acquired bilateral nevus of Ota-like macules, is a form of dermal melanocytosis found most commonly in women of East Asian heritage. It presents as discrete brown macules on the bilateral cheeks which later coalesce into confluent grey-brown macules and small patches. Herein, we report a classic case of Hori nevus and discuss the histologic findings and differential diagnosis. We also review the proposed pathophysiology, genetic considerations, and treatment options.

Bilateral epidermal nevi in the external auditory canals treated with CO2 laser.

Epidermal nevi are benign hamartomas of the epidermis and adnexal structures of the skin. We present the case of epidermal nevi in the bilateral external auditory ear canals of an otherwise healthy 23-year-old woman treated with CO2 laser ablation.

Reprogramming of the chick retinal pigmented epithelium after retinal injury.

BACKGROUND: One of the promises in regenerative medicine is to regenerate or replace damaged tissues. The embryonic chick can regenerate its retina by transdifferentiation of the retinal pigmented epithelium (RPE) and by activation of stem/progenitor cells present in the ciliary margin. These two ways of regeneration occur concomitantly when an external source of fibroblast growth factor 2 (FGF2) is present after injury (retinectomy). During the process of transdifferentiation, the RPE loses its pigmentation and is reprogrammed to become neuroepithelium, which differentiates to reconstitute the different cell types of the neural retina. Somatic mammalian cells can be reprogrammed to become induced pluripotent stem cells by ectopic expression of pluripotency-inducing factors such as Oct4, Sox2, Klf4, c-Myc and in some cases Nanog and Lin-28. However, there is limited information concerning the expression of these factors during natural regenerative processes. Organisms that are able to regenerate their organs could share similar mechanisms and factors with the reprogramming process of somatic cells. Herein, we investigate the expression of pluripotency-inducing factors in the RPE after retinectomy (injury) and during transdifferentiation in the presence of FGF2. RESULTS: We present evidence that upon injury, the quiescent (p27(Kip1)+/BrdU-) RPE cells transiently dedifferentiate and express sox2, c-myc and klf4 along with eye field transcriptional factors and display a differential up-regulation of alternative splice variants of pax6. However, this transient process of dedifferentiation is not sustained unless FGF2 is present. We have identified lin-28 as a downstream target of FGF2 during the process of retina regeneration. Moreover, we show that overexpression of lin-28 after retinectomy was sufficient to induce transdifferentiation of the RPE in the absence of FGF2. CONCLUSION: These findings delineate in detail the molecular changes that take place in the RPE during the process of transdifferentiation in the embryonic chick, and specifically identify Lin-28 as an important factor in this process. We propose a novel model in which injury signals initiate RPE dedifferentiation, while FGF2 up-regulates Lin-28, allowing for RPE transdifferentiation to proceed.

Cutaneous T-Cell Lymphoma Treatment: Case Series of Combination Therapy With Intralesional Injections of 5-Fluorouracil and Topical Imiquimod.

Cutaneous T-cell lymphoma (CTCL) is a chronic form of skin cancer. Skin-directed therapies rarely achieve complete clearance of lesions, and recurrences are frequent. In this case series, 9 patients with stage IA to IVA2 CTCL received intralesional (IL) therapy with 5-fluorouracil (5-FU) and imiquimod (IMQ) cream 5% daily to recalcitrant plaques and tumors. All 9 patients attained a complete response (CR) with no recurrences reported and no severe side effects. We find that combination IL 5-FU and IMQ cream 5% daily is a well-tolerated, effective, and durable skin-directed therapy for recalcitrant plaques and tumors in CTCL.

Dermatologic manifestations of COVID-19-associated multisystem inflammatory syndrome in children.

Multisystem inflammatory syndrome in children (MIS-C) affects a small percentage of pediatric patients infected with COVID-19 and is characterized by fever, laboratory evidence of inflammation, multisystem involvement, and severe illness necessitating hospitalization. Skin findings are often present in these patients, and when initially compared with Kawasaki disease, they likely represent distinct phenomena and overall remain poorly characterized. In this retrospective review of 34 case reports and series, we identified cutaneous manifestations documented in 417 of 736 patients (57%) with MIS-C associated with COVID-19. "Rash" was the sole descriptor of skin findings in nearly half of patients. Case reports and smaller case series provided more detail, outlining a broad range of lesion morphologies (polymorphic, maculopapular, morbilliform, erythrodermic, urticarial, reticular, petechial, purpuric) in variable anatomic distribution. More thorough descriptions of dermatologic manifestations in patients with MIS-C are warranted to better characterize this syndrome, as they may lend important insight into pathogenic mechanisms of disease.