This selection from the NCCN Guidelines for Merkel Cell Carcinoma (MCC) focuses on areas impacted by recently emerging data, including sections describing MCC risk factors, diagnosis, workup, follow-up, and management of advanced disease with radiation and systemic therapy. Included in these sections are discussion of the new recommendations for use of Merkel cell polyomavirus as a biomarker and new recommendations for use of checkpoint immunotherapies to treat metastatic or unresectable disease. The next update of the complete version of the NCCN Guidelines for MCC will include more detailed information about elements of pathology and addresses additional aspects of management of MCC, including surgical management of the primary tumor and draining nodal basin, radiation therapy as primary treatment, and management of recurrence.

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IMPORTANCEThere is a paucity of evidence to guide physicians regarding prevention strategies for cutaneous squamous cell carcinoma (CSCC) in solid organ transplant recipients (SOTRs).OBJECTIVE To examine the development and results of a Delphi process initiated to identify consensus-based medical management recommendations for prevention of CSCC in SOTRs.EVIDENCE REVIEW Dermatologists with more than 5 years' experience treating SOTRs were invited to participate. A novel actinic damage and skin cancer index (AD-SCI), consisting of 6 ordinal stages corresponding to an increasing burden of actinic damage and CSCC, was used to guide survey design. Three sequential web-based surveys were administered from January 1, 2019, to December 31, 2020. Pursuant to Delphi principles, respondents thoroughly reviewed all peer responses between rounds. Supplemental questions were also asked to better understand panelists' rationale for their responses.FINDINGS The Delphi panel comprised 48 dermatologists. Respondents represented 13 countries, with 27 (56%) from the US. Twenty-nine respondents (60%) were Mohs surgeons. Consensus was reached with 80% or higher concordance among respondents when presented with a statement, question, or management strategy pertaining to prevention of CSCC in SOTRs. A near-consensus category of 70% to less than 80% concordance was also defined. The AD-SCI stage-based recommendations were established if consensus or near-consensus was achieved. The panel was able to make recommendations for 5 of 6 AD-SCI stages. Key recommendations include the following: cryotherapy for scattered actinic keratosis (AK); field therapy for AK when grouped in 1 anatomical area, unless AKs are thick in which case field therapy and cryotherapy were recommended; combination lesion directed and field therapy with fluorouracil for field cancerized skin; and initiation of acitretin therapy and discussion of immunosuppression reduction or modification for patients who develop multiple skin cancers at a high rate (10 CSCCs per year) or develop high-risk CSCC (defined by a tumor with approximately Ն20% risk of nodal metastasis). No consensus recommendation was achieved for SOTRs with a first low risk CSCC.CONCLUSIONS AND RELEVANCE Physicians may consider implementation of panel recommendations for prevention of CSCC in SOTRs while awaiting high-level-of-evidence data. Additional clinical trials are needed in areas where consensus was not reached.

IntroductionScarring is an unfortunate clinical outcome of acne. Current treatment options for atrophic acne scars are dominated by non-pharmacological, invasive procedures which may not be suitable or affordable to all patients. This phase II, single-center, open-label, exploratory study assessed the efficacy, safety and subject-reported outcomes of adapalene 0.3% gel in the treatment of atrophic acne scars.MethodsThe study included subjects aged 18–50 years with past history of acne and moderate to severe facial atrophic acne scars. Subjects received adapalene 0.3% gel once daily for the first 4 weeks and twice daily for the following 20 weeks. Assessments were performed at baseline, day 10 and weeks 4, 8, 16 and 24, and at post-treatment follow-ups (weeks 36 and 48–72).ResultsAt week 24, investigator and subject assessments reported improvement in skin texture/atrophic scars in 50% and > 80% of subjects, respectively. Subjects were satisfied with the treatment and reported improvements in quality of life.ConclusionDaily use of adapalene 0.3% gel for the treatment of atrophic acne scars showed promising clinical efficacy, a favorable tolerability profile, and improvement in quality of life.FundingNestlé Skin Health–Galderma R&D.Trial RegistrationClinicalTrials.gov Identifier NCT01213199.

Human polyomavirus-7-associated rash and pruritus (PVARP) is a chronic superficial viral skin infection, which primarily impacts immunocompromised individuals. We report on a case of PVARP in a lung transplant recipient. Our patient developed symptoms 13 years after being on his immunosuppressive regimen, with an insidious course of progressive gray lichenification with marked islands of sparing and quality of life-altering pruritus. Treatment for PVARP is not established; however, topical cidofovir combined with immunomodulation may offer sustained therapeutic benefit.

Over the past several years, reports describing the administration of anti-programmed cell death-1 (PD-1) or other immune checkpoint inhibitors (ICIs) to solid organ transplant recipients (SOTRs) with advanced cancers have emerged with increasing frequency. 1 However, there is a paucity of data about the durability of antitumor and anti-allograft immunity in this chronically immunosuppressed patient population, which makes assessment of suitability for retransplantation challenging. Here, we describe the first reported

Macular lymphocytic arteritis or lymphocytic thrombophilic arteritis (LTA) is a recently described cutaneous arteritis that is characterized by asymptomatic macules and patches of the extremities associated with lymphocytic arteritis at the deep dermal/subcuticular junction for which little information exists on demographics, evaluation, and management. There has been recent debate in the literature whether this disease is a new distinct entity, misdiagnosed cutaneous polyarteritis nodosa (cPAN), or a disease on a spectrum with cPAN. We systematically review the literature on demographic information, medical history, histopathology findings, and treatment management to analyze trends and clarify controversies in characterizations of LTA. Forty detailed cases of LTA have been published. We submit that, although literature is limited, a review of the data still suggests that LTA is distinct from cPAN and systemic PAN. In addition, to better reflect the pathophysiologic natural history of this condition and correct for the historical artifact of how the disease was identified, we encourage the disease to be referred to as LTA and discourage ongoing use of macular lymphocytic arteritis.

Cutaneous eruptions are among the most common immune-related adverse events (irAEs) associated with anti-PD-1/PD-L1 therapy, and are often clinically and histologically characterized as lichenoid. Non-lichenoid patterns may also occur and are likely to be encountered by surgical pathologists, given the increasing clinical use of these agents. The purpose of this study is to describe the histopathologic features of non-lichenoid cutaneous irAEs from patients receiving anti-PD-1/PD-L1 therapies for a variety of underlying advanced malignancies. Sixteen patients with 17 biopsied eruptions were included from two academic institutions with extensive experience administering and monitoring responses to immune checkpoint blockade as well as treating the potential side effects. Eruptions occurred a median of 10 days (range 1 day to 11.4 months) after treatment initiation. Nearly half of specimens demonstrated either a psoriasiform/spongiotic or an urticarial-type reaction pattern on histologic review. Patterns consistent with Grover’s disease, bullous pemphigoid, and granulomatous dermatitis were also observed. Nearly two-thirds of patients required systemic corticosteroids for treatment of the cutaneous irAE, and 19% of patients discontinued immunotherapy due to their skin eruptions. 75% of patients showed an objective antitumor response. The diverse array of non-lichenoid cutaneous irAE presented here should reflect and inform the scope of histologic patterns encountered by the practicing surgical pathologist. Such eruptions are seen in patients with a variety of underlying tumor types, many of whom ultimately demonstrate a favorable response to immune checkpoint blockade.