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Background: Cutaneous lichen planus (LP) is a recalcitrant, difficult-to-treat, inflammatory skin disease characterized by pruritic, flat-topped, violaceous papules on the skin. Baricitinib is an oral Janus kinase (JAK) 1/2 inhibitor that interrupts the signaling pathway of interferon gamma (IFN)-γ, a cytokine implicated in the pathogenesis of LP., Methods: In this phase II trial, twelve patients with cutaneous LP received baricitinib 2 mg daily for 16 weeks, accompanied by in-depth spatial, single-cell, and bulk transcriptomic profiling of pre- and post-treatment samples., Results: An early and sustained clinical response was seen, with 83.3% of patients responsive at week 16. Our molecular data identified a unique, oligoclonal IFN-γ, CD8+, CXCL13+ cytotoxic T-cell population in LP skin and demonstrated a rapid decrease in IFN signature within 2 weeks of treatment, most prominently in the basal layer of the epidermis., Conclusion: This study demonstrates the efficacy and molecular mechanisms of JAK inhibition in LP., Trial Registration: NCT05188521.ROLE OF FUNDING SOURCE. Eli Lilly, Appignani Benefactor Funds, 5P30AR075043, Mayo Clinic Clinical Trials Stimulus Funds.

Competing Interests: Conflicts of interest Dr Ruiz serves is a consultant for Regeneron, Checkpoint Therapeutic, Feldan Pharmaceuticals. She serves as a Principal Investigator/Co-Investigator for the following companies: Regeneron (PI/Co-I), Merck (Co-I), Castle Biosciences (Co-I) and is the Executive Officer of Skin Cancer Outcomes Consortium (SCOUT) Skin Cancer Champions. Dr Carr is an investigator for Regeneron (no direct funds). Dr Cañueto has the following disclosures: grants to institution: Sanofi/Regeneron, Castle Biosciences; Lectures honoraria: Sanofi, Almirall, AbbVie, Regeneron, Sun Pharma; Payment for expert testimony: Sanofi, Regeneron, Almirall; Support for attending meetings: Pfizer, Almirall, Lilly, Castle Biosciences; Advisory board: Almirall, Sanofi, Regeneron, Kyowa, Roche, InflaRx; Funding: support by the Gerencia Regional de Salud de Castilla y León (GRS2549/A/22) and by the Instituto de Salud Carlos III (PI21/01207), co-financed by European Union. Dr Mangold has patent Methods and Materials for assessing and treating cutaneous squamous cell carcinoma (provisional 63-423254) and Regeneron Consulting with payments to the institution. He has consulted for Kyowa, Eli Lilly, Momenta, UCB, and Regeneron in the past, greater than 24 months ago. He has consulted for PHELEC in the past, great than 12 months. He has consulted for Incyte, Soligenix, Clarivate, and Bristol Myers Squibb in the past, less than 12 months ago. He consults for Nuvig, Argenyx, Boehringer, Janssen, and Ingelheim currently. He consults for Pfizer currently with payments to the institution. He has grant support from Kyowa, Miragen, Regeneron, Corbus, Pfizer, Incyte, Eli Lilly, Aregenx, Palbella, AbbVie, Priovant, Merck in the last 24 months. Beyond 24 months, grant support has come from Sun Pharma, Elorac, Novartis, and Janssen. His current patents include the use of oral JAKi in Lichen Planus (provisional 63/453,065), and Topical Ruxolitinib in Lichen Planus (WO2022072814A1). Dr Carucci receives funding for investigator initiated basic science research from Regeneron and is a PI for a clinical trial sponsored by Regeneron. Dr Koyfman has the following disclosures: Advisory board (paid): Merck, BMS, Regeneron, Galera therapeutics; Advisory board (unpaid): Castle Biosciences; Research support: Castle biosciences, merck, BMS, Regeneron; Honoraria: UpToDate. Dr Vidimos has the following dicslosures: Research Support – Castle; Advisory Board - Inhibitor Therapeutics; Honoraria - Up to Date. Dr Wysong has received an institutional research grant from Castle Biosciences. Drs Granger, Ran, Groover, Shahwan, Hirotsu, Carter, Girardi, Brodland, Sruvastava, Zitelli, and Willenbrink have no conflicts of interest to declare.

Background: Combination immune checkpoint blockade targeting PD-1 and CTLA-4 leads to high response rates and improved survival in advanced cutaneous melanoma (CM). Less is known about the efficacy of this combination in acral lentiginous melanoma (ALM)., Objectives: To determine the efficacy of combination immune checkpoint blockade targeting PD-1 and CTLA-4 in a real-world, diverse population of ALM., Methods: This multi-institutional retrospective study analyzed patients with histologically confirmed ALM treated with the combination of PD-1 and CTLA-4 inhibitors between 2010-2022. The primary objective of the study was objective response rate (ORR) per RECIST criteria. The secondary objectives were progression-free survival (PFS) and overall survival (OS)., Results: In total, 109 patients with advanced ALM treated with combined PD-1 and CTLA-4 blockade in any line of treatment were included. The majority of patients had stage IV disease (n=81, 74.2%). The ORR for the entire cohort was 18.3% (95% CI 11.6-26.9%), with 9 (8.3%) complete responses (CR) and 11 (10.1%) partial responses (PR). An additional 22 patients (20.2%) had stable disease (SD), and the disease control rate (DCR) was 38.5%. The median PFS was 4.2 months [95% CI 3.25-5.62], while the median OS was 17 months [95% CI 12.4%-23.1%]. A total of 95 patients (87.2%) had a treatment-related adverse event, with 40.4% (n=44/109) experiencing at least one grade 3 or 4 toxicity. Elevated LDH (p=.04), 2+ lines of prior therapy (p=.03), and Asian race/ethnicity (p=.04) were associated with worse OS, while Hispanic/Latino race/ethnicity was associated with better OS (p=.02)., Conclusions: Combination of PD-1 and CTLA-4 blockade is less effective for ALM, as compared to CM, despite similar toxicity. Asian patients, in particular, appear to derive lower benefit from this regimen. Novel treatment approaches are needed for this rare melanoma subtype., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Association of Dermatologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Competing Interests: Dr Costello is an investigator for DeepX Health and Merck. Dr Mangold has consulted for Kyowa, Eli Lilly, Momenta, UCB, and Regeneron in the past, greater than 24 months ago. He has consulted for PHELEC in the past, great than 12 months. He has consulted for Incyte, Soligenix, Clarivate, and Bristol Myers Squibb in the past, less than 12 months ago. He consults for Argenyx, Boehringer, Janssen, and Ingelheim currently. He consults for Regeneron and Pfizer currently with payments to the institution. He received grant support from Kyowa, Miragen, Regeneron, Corbus, Pfizer, Incyte, Eli Lilly, Aregenx, Palbella, Abbvie, Priovant, Merck in the last 24 months. Beyond 24 months, grant support has come from Sun Pharma, Elorac, Novartis, and Janssen. His current patents include Methods and Materials for assessing and treating cutaneous squamous cell carcinoma (provisional 63-423254), use of oral JAKi in Lichen Planus (provisional 63/453065), and Topical Ruxolitinib in Lichen Planus (WO2022072814A1). Dr Dhaliwal and Authors Greene and Ho have no conflicts of interest to declare.

Importance: Office-based phototherapy is cost-effective for psoriasis but difficult to access. Home-based phototherapy is patient preferred but has limited clinical data, particularly in patients with darker skin., Objective: To compare the effectiveness of home- vs office-based narrowband UV-B phototherapy for psoriasis., Design, Setting, and Participants: The Light Treatment Effectiveness study was an investigator-initiated, pragmatic, open-label, parallel-group, multicenter, noninferiority randomized clinical trial embedded in routine care at 42 academic and private clinical dermatology practices in the US. Enrollment occurred from March 1, 2019, to December 4, 2023, with follow-up through June 2024. Participants were 12 years and older with plaque or guttate psoriasis who were candidates for home- and office-based phototherapy., Interventions: Participants were randomized to receive a home narrowband UV-B machine with guided mode dosimetry or routine care with office-based narrowband UV-B for 12 weeks, followed by an additional 12-week observation period., Main Outcomes and Measures: The coprimary effectiveness outcomes were Physician Global Assessment (PGA) dichotomized as clear/almost clear skin (score of ≤1) at the end of the intervention period and Dermatology Life Quality Index (DLQI) score of 5 or lower (no to small effect on quality of life) at week 12., Results: Of 783 patients enrolled (mean [SD] age, 48.0 [15.5] years; 376 [48.0%] female), 393 received home-based phototherapy and 390 received office-based phototherapy, with 350 (44.7%) having skin phototype (SPT) I/II, 350 (44.7%) having SPT III/IV, and 83 (10.6%) having SPT V/VI. A total of 93 patients (11.9%) were receiving systemic treatment. At baseline, mean (SD) PGA was 2.7 (0.8) and DLQI was 12.2 (7.2). At week 12, 129 patients (32.8%) receiving home-based phototherapy and 100 patients (25.6%) receiving office-based phototherapy achieved clear/almost clear skin, and 206 (52.4%) and 131 (33.6%) achieved DLQI of 5 or lower, respectively. Home-based phototherapy was noninferior to office-based phototherapy for PGA and DLQI in the overall population and across all SPTs. Home-based phototherapy, compared to office-based phototherapy, was associated with better treatment adherence (202 patients [51.4%] vs 62 patients [15.9%]; P < .001), lower burden of indirect costs to patients, and more episodes of persistent erythema (466 of 7957 treatments [5.9%] vs 46 of 3934 treatments [1.2%]; P < .001). Both treatments were well tolerated with no discontinuations due to adverse events., Conclusions and Relevance: In this randomized clinical trial, home-based phototherapy was as effective as office-based phototherapy for plaque or guttate psoriasis in everyday clinical practice and had less burden to patients., Trial Registration: ClinicalTrials.gov Identifier: NCT03726489.

Competing Interests: None disclosed.

Background: Bullous pemphigoid (BP) is a rare, autoimmune, blistering skin disease associated with high disease burden, profoundly decreased quality of life and increased morbidity. Emerging evidence supports an important role for type 2 inflammation in disease pathogenesis. Current management relies on topical and/or systemic corticosteroids, non-selective immunosuppressants and antibiotics with anti-inflammatory properties, which are all limited by side effects and toxicities. Therefore, targeted, efficacious and safe therapies are needed. Dupilumab blocks the shared receptor component for interleukin (IL)-4 and IL-13, key and central drivers of type 2 inflammation. Several reports of patients successfully treated with dupilumab have been published; however, dupilumab has not been formally assessed in a double-blind, placebo-controlled trial., Objectives: We report the design of LIBERTY-BP ADEPT, a multicenter, randomized, double-blind, placebo-controlled clinical trial to evaluate the efficacy and safety of dupilumab in adults with BP., Methods: LIBERTY-BP ADEPT comprises a 35-day screening, 52-week treatment and 12-week follow-up period. Approximately 98 adults aged 18-90 years with moderate-to-severe BP are being enrolled at 51 sites on 4 continents and randomized 1:1 to subcutaneous dupilumab or placebo every 2 weeks. All participants will receive concomitant oral corticosteroids (OCS)., Planned Outcomes: The primary endpoint is the proportion of patients achieving complete remission off steroid therapy at week 36. Key secondary endpoints include total cumulative OCS dose to week 36, percent change and proportion of patients with ≥ 4-point reduction in the weekly average of daily Peak Pruritus Numerical Rating Scale from baseline to week 36 and percent change in Bullous Pemphigoid Area Index score from baseline to week 36., Conclusion: The trial results will provide evidence on whether the efficacy and safety of dupilumab support its use as a potential novel treatment approach for BP and will provide new insights into the role of type 2 inflammation in BP pathogenesis., Clinical Trial Registration: ClinicalTrials.gov identifier NCT04206553., (© 2024. Crown.)

Drug repurposing is an attractive strategy for therapy development, particularly in rare diseases where traditional drug development approaches may be challenging owing to high cost and small numbers of patients. In this study, we used a drug identification and repurposing pipeline to identify candidate targetable drivers of disease and corresponding therapies through application of causal reasoning using a combination of open-access resources and transcriptomics data. We optimized our approach on psoriasis as a disease model, demonstrating the ability to identify known and, to date, unrecognized molecular drivers of psoriasis and link them to current and emerging therapies. Application of our approach to a cohort of tissue samples of necrobiosis lipoidica (an unrelated; rare; and, to date, molecularly poorly characterized cutaneous inflammatory disorder) identified a unique set of upstream regulators, particularly highlighting the role of IFNG and the Jak-signal transducer and activator of transcription pathway as a likely driver of disease pathogenesis and linked it to Jak inhibitors as potential therapy. Analysis of an independent cohort of necrobiosis lipoidica samples validated these findings, with the overall agreement of drug-matched upstream regulators above 96%. These data highlight the utility of our approach in rare diseases and offer an opportunity for drug discovery in other rare diseases in dermatology and beyond., (© 2024 Published by Elsevier Inc. on behalf of the Society for Investigative Dermatology.)

Background/aim: Total skin electron beam therapy (TSEBT) is an effective treatment for managing cutaneous T-cell lymphoma (CTCL), but may result in unnecessary toxicity. With the production of a custom rolling shield holding a configurable stack of plastic slats to block uninvolved skin, we implemented a program for subtotal skin electron beam therapy (STSEBT). We report our preliminary experience with STSEBT vs. TSEBT to manage CTCL., Patients and Methods: A retrospective review of 32 CTCL patients who were treated at a single institution between February 28th, 2017, and May 25th, 2022, was completed. Of these cases, seven patients received STSEBT and 25 received TSEBT., Results: Thirty-two patients underwent a course of STSEBT or TSEBT. The median follow-up was 465 days and the median age at diagnosis was 70.8 years. Stage distribution was as follows: one (3%) IA, 16 (50%) IB, 6 (19%) IIB, two (6%) IIIA, five (16%) IVA, and two (6%) IVB. The overall response rate was 96%. For patients receiving TSEBT (n=25), three (12%), 10 (40%), and 11 (44%) had a CR, NCR, and PR, respectively. For the patients receiving STSEBT, four (57.1%), three (42.9%), and zero (0%) had a CR, NCR, and PR, respectively. There was one patient (4%) with no response. Cumulative incidence of progressive skin disease requiring additional electron therapy at three months was 21.1% [IQR=8.6, 51.5%], 36.8% [IQR=20, 68%] at six months, and 57.9% [IQR=38.5, 87.1%] at one year. Low rates of toxicities were recorded., Conclusion: This analysis demonstrated that treatment of CTCL patients with low disease burden with STSEBT results in similar overall response and time to progression compared to treatment with TSEBT., (Copyright © 2024 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Purpose: Low-dose total skin electron beam therapy (TSEBT) is a proven treatment for managing cutaneous T-cell lymphoma (CTCL) and Sezary syndrome with skin burden. We performed a retrospective comparison of response rates and time to progression for patients receiving low-dose TSEBT based on dose per fractionation, total dose, and stage., Methods and Materials: One hundred and ten patients with CTCL and Sezary syndrome were treated with 135 courses of low-dose (400-1500 cGy) TSEBT or subtotal skin electron therapy at multiple centers of a single institution between August 2003 and June 2023. Patients were stratified according to total dose, dose per fraction, and stage., Results: The median follow-up was 301 days (IQR, 141, 767). The median age at treatment was 69.9 years (range, 29.7-96.5). T-stage distribution was as follows: 3 (2.7%) T1, 74 (67.3%) T2, 16 (14.5%) T3, and 17 (15.5%) T4. American Joint Committee on Cancer eighth edition stage distribution was as follows: 3 (2.7%) IA, 53 (48.2%) IB, 3 (2.7%) IIA, 16 (14.5%) IIB, 8 (7.3%) IIIA, 19 (17.3%) IVA, and 8 (7.3%) IVB. There was no significant difference in disease distribution between patients treated with different fractionation schemes. The overall response rate was 89.6%. Forty-four courses (32.6%), 34 courses (25.2%), and 43 (31.9%) resulted in a complete, near-complete, and partial response, respectively. Fourteen courses (10.4%) resulted in no clinical response. For all patients, the median time to response was 43.0 days (IQR, 23.0-70). The median time to skin progression for all patients was 107.5 days (IQR, 67.8-233.5)., Conclusions: This analysis demonstrated that CTCL patients treated with low-dose radiation therapy delivered over various fractionation schemes had similar overall response rates and median time to progression., Competing Interests: Aaron Mangold has received funding from Regeneron, Corbus Sun Pharma, Incyte, Pharma, Eli Lilly, Elorac, Novartis, Janssen, Soligenix, Argenx, Palvella, Abbvie, Priovant, and Merck. All other authors have no relevant conflicts of interest to disclose., (© 2024 The Authors.)

BACKGROUND: Hidradenitis suppurativa (HS) is a debilitating, inflammatory skin disease with limited treatment options and partially understood pathophysiology. Using an umbrella trial design, three kinase inhibitor immunomodulators with different mechanisms of action were evaluated. METHODS: This phase 2a, double-blind, parallel-group trial enrolled adults with moderate to severe HS who were then randomly assigned (1:1:1:1) to once-daily brepocitinib 45 mg (a JAK1/TYK2 inhibitor), zimlovisertib 400 mg (an IRAK4 inhibitor), ropsacitinib 400 mg (a TYK2 inhibitor), or matching placebo for 16 weeks. The primary end point was the percentage of participants achieving HS clinical response (HiSCR) at week 16. Safety, including treatment-emergent adverse events (TEAEs), was monitored throughout. RESULTS: Totals of 52, 47, 47, and 48 participants were assigned to brepocitinib, zimlovisertib, ropsacitinib, and placebo, respectively. At week 16, 28% were lost to follow-up and assumed to be nonresponders; HiSCR occurred in 33.3% (16/48) of participants receiving placebo and in 51.9% (27/52), 34.0% (16/47), and 37.0% (17/46) of those receiving brepocitinib, zimlovisertib, and ropsacitinib (difference in percentage points vs. placebo [90% confidence interval], 18.7 [2.7 to 34.6], 0.7 [−15.2 to 16.7], and 3.5 [−12.6 to 19.6]), respectively. TEAEs occurred more frequently with active treatment (brepocitinib, 30 [57.7%]; zimlovisertib, 26 [55.3%]; ropsacitinib, 29 [61.7%]; placebo, 23 [47.9%]). Most TEAEs (infections, skin disorders, and gastrointestinal symptoms) were mild; there were no deaths. CONCLUSIONS: Participants with moderate to severe HS treated with brepocitinib experienced greater clinical response, whereas those on zimlovisertib and ropsacitinib did not, compared with placebo. These results favor the JAK/STAT pathway as an immunologic target in HS and did not confirm a role for selective IRAK4 or TYK2 inhibition. These results should be confirmed in larger studies with longer follow-up. (Funded by Pfizer; ClinicalTrials.gov registration number, NCT04092452.)

Background: Delivery of dermatologic care through telemedicine was accelerated by the COVID-19 pandemic. We sought to analyze the teledermatology experience across Mayo Clinic's health care system to identify strengths and limitations of teledermatology., Methods: Electronic health records of dermatology televisits were reviewed from multiple U.S. Mayo Clinic sites from January 2020 through January 2021., Results: A total of 13,181 dermatology televisits were conducted in 6468 unique patients. Patients were primarily female (60.2%), and mean age of all patients was 34.1 years. Synchronous / live video conferencing visits were the most common (40.0%) telecare modality. Synchronous / live audio conferencing and asynchronous / store-and-forward visits comprised 33.0% and 27.0% of appointments. In total, 3944 televisits (29.9%) were successfully concluded via a single appointment. An in-person appointment was needed for 1693 patients (26.2%) after their initial televisit. For patients with a single televisit, synchronous / live video conferencing was the most common virtual modality (58.0% vs 32.2% of patients with multiple visits, p  < 0.001). Patients needing in-person follow-up visits were slightly older than those who did not (mean [SD], 38.8 [22.3] vs 35.0 [23.6] years; p  < 0.001) but without any sex-based difference. Around one-third of patients needed an in-person follow-up visit after their initial asynchronous / store-and-forward visit which was higher when compared with synchronous / live audio and video conferencing., Conclusion: Single dermatology televisits effectively managed nearly one-third of patients who did not require in-person follow-up. An initial synchronous / live video conferencing was more likely to yield a single clinical encounter, whereas asynchronous / store-and-forward visits required more in-person follow-up. Future studies are required that focus on dermatology-specific cost, diagnoses, access, quality of care, and outcomes., Competing Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2024.)

Patching whole slide images (WSIs) is an important task in computational pathology. While most of them are designed to classify or detect the presence of pathological lesions in a WSI, the confounding role and redundant nature of normal histology are generally overlooked. In this paper, we propose and validate the concept of an "atlas of normal tissue" solely using samples of WSIs obtained from normal biopsies. Such atlases can be employed to eliminate normal fragments of tissue samples and hence increase the representativeness of the remaining patches. We tested our proposed method by establishing a normal atlas using 107 normal skin WSIs and demonstrated how established search engines like Yottixel can be improved. We used 553 WSIs of cutaneous squamous cell carcinoma to demonstrate the advantage. We also validated our method applied to an external dataset of 451 breast WSIs. The number of selected WSI patches was reduced by 30% to 50% after utilizing the proposed normal atlas while maintaining the same indexing and search performance in leave-one-patient-out validation for both datasets. We show that the proposed concept of establishing and using a normal atlas shows promise for unsupervised selection of the most representative patches of the abnormal WSI patches., (© 2024. The Author(s).)

Background: Immunotherapies have changed the landscape of late-stage melanoma; however, data evaluating timely access to immunotherapy are lacking., Methods: A retrospective cohort study utilizing the National Cancer Database was conducted. Stage III and IV melanoma cases diagnosed between 2011 and 2018 that received systemic treatment with either immunotherapy or chemotherapy were included. Chemotherapy included BRAF/MEK inhibitors. Multivariable logistic regression models were utilized to evaluate factors associated with the likelihood of receiving immunotherapy as primary systemic treatment relative to chemotherapy; additionally, Cox proportional hazards models were utilized to incorporate time from diagnosis to primary systemic therapy into the analysis., Results: The study population was comprised of 14,446 cases. The cohort included 12,053 (83.4%) immunotherapy and 2393 (16.6%) chemotherapy cases. In multivariable logistic regression analysis, factors significantly associated with immunotherapy receipt included population density, circle distance, year of diagnosis, Breslow thickness, and cancer stage. Immunotherapy timing was evaluated using multivariable Cox regression analysis. Minorities were less likely to receive timely immunotherapy than non-Hispanic Whites (HR 0.83, CI 0.74-0.93, p = 0.001). Patients at circle distances of 10-49 miles (HR 0.94, CI 0.89-0.99, p = 0.02) and ≥50 miles (HR 0.83, CI 0.77-0.90, p < 0.001) were less likely to receive timely immunotherapy., Conclusion: Patients traveling ≥10 miles and minorities have a decreased likelihood of receiving timely immunotherapy administration for primary systemic treatment. Future research is needed to identify what barriers and approaches can be leveraged to address these inequities., (© 2024 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Background: Necrobiosis lipoidica (NL) is a rare, idiopathic, and recalcitrant disease of collagen degeneration for which treatment options have been poorly studied. Due to its recurring nature, risk for ulceration, and high morbidity, there is a need to understand existing treatment modalities to better inform clinical care., Objective: This review aims to describe the therapeutic modalities reported in the literature for the treatment of NL., Methods: A literature search of treatments was performed by searching for publications between January 2016 and May 2022 on PubMed and Scopus. Given the limited high-quality evidence, case reports and series were included. Only publications presenting information on both attempted treatments and outcomes were included., Results: A total of 60 novel articles were identified (54 case reports, two case series, and four retrospective cohort studies). These studies cumulatively reported on 274 patients and covered treatments including phototherapy, topical corticosteroids, topical calcineurin inhibitors, biologics, immunosuppressants, JAK inhibitors, combination therapies, and several others. The greatest amount of evidence was found for photodynamic therapy (improvement in 72 of 80 patients), UVA-based phototherapy (12 of 33), topical corticosteroids (21 of 46), compression therapy (15 of 20), and topical calcineurin inhibitors (11 of 17). Several newer treatments were also described, including ustekinumab and JAK inhibitors., Conclusions: This systematic review provides a comprehensive summary of recently published treatments for NL. As the existing data comes predominantly from case reports and series, statistical conclusions are not assessed. A greater number of randomized controlled trials with standardized endpoints are necessary to compare treatment efficacy., (© 2023 The Authors. International Journal of Dermatology published by Wiley Periodicals LLC on behalf of the International Society of Dermatology.)

Competing Interests: Author Costello has no relevant disclosures; unrelated to this study, he is an investigator for DeepX Health. Author Mangold has no relevant disclosures; he has consulted for Kyowa, Eli Lilly, Momenta, UCB, and Regeneron in the past, greater than 24 months ago; he has consulted for PHELEC in the past, greater than 12 months; he has consulted for Incyte, Soligenix, Clarivate, and Bristol Myers Squibb in the past, less than 12 months ago; he consults for Argenyx, Boehringer, Janssen, and Ingelheim currently; he consults for Regeneron and Pfizer currently with payments to the institution; he has grant support from Kyowa, Miragen, Regeneron, Corbus, Pfizer, Incyte, Eli Lilly, Aregenx, Palbella, Abbvie, Priovant, Merck in the last 24 months; beyond 24 months, grant support has come from Sun Pharma, Elorac, Novartis, and Janssen; and his current patents include Methods and Materials for assessing and treating cutaneous squamous cell carcinoma (provisional 63-423254), use of oral JAKi in Lichen Planus (provisional 63/453,065), and Topical Ruxolitinib in Lichen Planus (WO2022072814A1). Author Leachman has received unrestricted educational grant 18 months ago from Caste Biosciences and has been compensated for Orlucent MSAB within 24 months, and Merk MSAB co within 18 months; she has also served as the Co-I on Veriskin: clinical protocol uncompensated, Palvella: MSAB, Local CO-I for Pachyonychia congenita therapeutic uncompensated, and currently is working on Pathology Watch: MSAB research project support uncompensated. All other authors have no conflicts of interest and no financial disclosures.

Importance: Patients are frequently copositive for multiple allergens simultaneously, either due to chemical similarity or simultaneous sensitization. A better understanding of copositivity groups would help guide contact avoidance., Objective: To use patient data to systematically determine copositivity groups in the Mayo Clinic Standard Series., Design, Setting, and Participants: In this retrospective cross-sectional analysis, the Mayo Clinic patch test database was queried for pairwise copositivity rates in the 80 allergen Mayo Clinic Standard Series between 2012 and 2021. Data were collected from 3 tertiary care sites of the Mayo Clinic Contact Dermatitis Group and a total of 5943 patients were included, comprising all patients undergoing patch testing to the Mayo Clinic Standard Series allergens., Main Outcomes and Measures: Copositivity rates between every 2 allergens in the 80-allergen Mayo Clinic Standard Series were estimated. After background correction, copositivity rates were analyzed using unsupervised hierarchical clustering to systematically identify copositivity groups in an unbiased manner., Results: Overall, 394 921 total patches were applied to 5943 patients (4164 [70.1%] women, 1776 [29.9%] men, with a mean [SD] age of 52.3 [18.8] years ), comprising 9545 positive reactions. After background correction based on overall positivity rates, hierarchical clustering revealed distinct copositivity groups. Many were supported by prior literature, including formaldehyde releasers, cobalt-nickel-potassium dichromate, acrylates, 3-dimethylaminopropylamine-amidoamine-oleamidopropyl dimethylamine, alkyl glucosides, budesonide-hydrocortisone-17-butyrate, certain fragrances, compositae-sesquiterpene lactone mix, mercapto mix-mercaptobenzothiazole, carba mix-thiuram mix, and disperse orange-p-phenylenediamine. However, novel associations were also found, including glutaraldehyde-sorbitan sesquioleate, benzalkonium chloride-neomycin-bacitracin, bronopol-methylchloroisothiazolinone-methylisothiazolinone, and benzoic acid-iodopropynyl butylcarbamate., Conclusions and Relevance: This retrospective cross-sectional analysis found that copositivity rates varied between allergens; allergens with extremely high positivity rates demonstrated nonspecific copositivity to multiple other allergens. Background correction based on positivity rates followed by hierarchical clustering confirmed prior known copositivity groups, contaminants and/or excipients leading to copositivity, and novel associations to guide contact avoidance.

Lichen planus (LP) can affect multiple body sites including skin, mucosae, scalp and nails, causing considerable impact on patients' quality of life. Currently, there are no LP patient-reported outcome measures (PROMs) that address all body sites potentially affected by LP. We developed a LP Quality of Life Questionnaire (LPQoL), informed by an expert consortium and patient survey study, to address this gap. The study was approved by our institution's Institutional Review Board. First, a 22-item LPQoL was designed with input from LP experts at our institution. The tool was then optimized by garnering input from patients recently diagnosed with LP, who were asked to complete the LPQoL, as well as the Dermatology Life Quality Index (DLQI) and a feedback form about the LPQoL. Fifty-eight of 150 patients (39% response rate) returned the questionnaire. Mean DLQI score was 4.9 ± 5.6 SD (range 0-25) and mean LPQoL score was 13.6 ± 10.4 SD (range 0-54). LPQoL score was positively correlated with DLQI score (r = 0.79; p < 0.001). Forty-nine out of 56 (88%) and 6/56 (11%) rated the LPQoL as 'very easy' or 'fairly easy' to complete, respectively. Based on participants' feedback, we increased the recall period from one week to one month and added questions on esophageal involvement. With iterative input from LP experts and patients, we developed a LPQoL to address the gap in a multi-site PROM specific to LP. This is a pilot study and there is ongoing validation studies; therefore, this measure should not be used in clinical practice or research until validated., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Purpose: Subtotal skin electron beam therapy may be an option for patients with cutaneous lymphoma receiving radiation therapy to treat large areas of their skin but may benefit from sparing specific areas that may have had previous radiation therapy, are of specific cosmetic concern, and/or show no evidence of disease. We report here on the design, implementation, and dosimetric characteristics of a reusable and transparent customizable shield for use with the large fields used to deliver total skin electron beam therapy at extended distance with a conventional linear accelerator., Methods and Materials: A shield was designed and manufactured consisting of acrylic blocks that can be mounted on a steel frame to allow patient-specific shielding. The dosimetry of the device was measured using radiochromic film., Results: The shield is easy to use and well-tolerated for patient treatment, providing minimal electron transmission through the shield with a sharp penumbra at the field edge, with no increase in x-ray dose. We report on the dosimetry of a commercial device that has been used to treat more than 30 patients to date., Conclusions: The customizable shield is well suited to providing patient-specific shielding for subtotal skin electron beam therapy., Competing Interests: William Breen reports being on the scientific advisory board for GE Healthcare, with all payments made to his institution. John Lucido reports receiving an honorarium paid to his institution for work as grant referee for Global Bridges Oncology and consulting fees paid to his institution by Varian Medical Systems. Aaron Mangold reports currently receiving research grants paid to his institution by Regeneron, Corbus, Incyte, Pfizer, Eli Lilly, Argenyx, Palvella, Abbview, Priovant, and Merck and previous research grants in the past 36 months for Kyowa Kirin, Miragen, Sun Pharma, Elorac, Janssen, and Novartis. He also is currently receiving consulting fees paid to him from Janssen and Boehringer Ingelheim and paid to his institution from Argenyx, Incyte, Regeneron, Clarivate, and Pfizer, previously received consulting fees paid to him from Kyowa Kirin, Clarivate, Soligenix, Phlecs, Incyte, Eli Lilly, Momenta, UCB, and Bristol Myers Squibb, and is currently receiving payment for manuscript writing (for a separate manuscript) from Janssen. He holds a patent for “Topical Ruxolitinib for Treating Lichen Planus” (PCT/US2021/053149; 63/086,898) and has filed for a patent for “Methods and Materials for Assessing and Treating Cutaneous Squamous Cell Carcinoma” (63/423,254). Aaron Mangold is also currently on the Advisory Board for Bristol Myers Squibb currently the President of Pacific Dermatology Society, the Chair of the Community Outreach Committee for the American Academy of Dermatology, on the Board of Directors for the US Cutaneous Lymphoma Consortium, was previously the President of the Arizona Dermatology and Dermatological Society and a Board Member for the Arizona Medical Association (all unpaid), has personal stock ownership of Intellia Therapeutics and Editas, and is receiving medical writing support from Pfizer and Janssen. Chris Deufel reports being a board member of the American Brachytherapy Society., (© 2023 The Author(s).)

Hispanics are more likely to be diagnosed with skin cancer at a later stage and experience worse overall survival than Whites. The objective of this cross-sectional study was to assess the skin cancer knowledge, attitudes, perceived risk, and sun protection practices among an underserved population in the Phoenix area. We recruited participants from the greater Phoenix area to undergo skin examination and complete a questionnaire. 208 participants were included. The majority were Hispanic (64.9%). Of this Hispanic group, most were from Mexico (87.9%). The Hispanic cohort had an overall mean skin cancer knowledge score of 3.68/6, the lowest of any other racial/ethnic group, but had the highest desire to learn more about skin cancer (64.6%, "strongly agree"). They were the most concerned about developing skin cancer (50.4%, "very concerned") but had relatively lower rates of sun protection practices (7.9% "always use" sunscreen, 22.0% "always use" sun-protective clothing). Limitations of this study include a small sample size, lack of validation for the skin cancer knowledge score, lack of season as a covariate in the multivariate analysis, lack of follow-up, and lack of robust skin cancer risk assessment. In conclusion, despite poorer skin cancer knowledge and sun protection practices, the Hispanic population had the highest concern for developing skin cancer and desire to learn more about skin cancer. Targeted and culturally relevant skin cancer and sun protection education for this group is needed., (© 2022. W. Montague Cobb-NMA Health Institute.)

Background: Necrobiosis lipoidica (NL) is complicated by ulceration in up to 35% of cases., Methods: Retrospective study of patients with NL seen at our institution between January 1, 1992, and May 25, 2021, was conducted. Ulcerated NL (UNL, n = 83) and non-ulcerated NL (NUNL, n = 233) groups were compared., Results: Twenty-six percent (83/316) of patients with NL experienced ulceration. UNL was significantly more likely to be painful (52% vs. 36%, P = 0.01), was more likely to have a lesion-associated cutaneous malignancy (7% vs. 0%, P < 0.001), and had a larger median size (7 vs. 5 cm, P = 0.004) compared to NUNL. Vascular studies were performed on a subset of patients and revealed transcutaneous oxygen pressure (TcPO2) < 40 mm Hg in 53% and venous insufficiency in 62% with no significant differences between UNL and NUNL groups. In patients with unilateral ulceration, mean TcPO2 values (39.7 vs. 46.6 mm Hg), regional perfusion index <0.6 (29% vs. 14%), and TcPO2 < 40 mm Hg (43% vs. 14%) were worse in the ulcerated leg compared to the non-ulcerated leg, but these differences were not statistically significant., Conclusions: UNL was more likely to be painful, develop lesion-associated malignancy, and be larger in size compared to NUNL. There were no statistically significant differences in venous insufficiency, arterial Doppler/ankle brachial index, or TcPO2 values between UNL and NUNL patients, however, a significant portion of the cohort demonstrated abnormal vascular studies, particularly on TcPO2 and venous insufficiency testing., (© 2022 the International Society of Dermatology.)

Competing Interests: Conflicts of interest Drs Fox, Rosenbach, and Mangold are members of the Society of Dermatology Hospitalists. The Society of Dermatology Hospitalists was not involved in the design of the study, data collection, analysis, or drafting of the manuscript. Author Puri, Dr Pollock, Authors Yousif and Bhullar, and Drs Boudreaux and Pittelkow have no conflicts of interest to declare.

Cutaneous T-cell lymphomas (CTCLs) are a spectrum of diseases with varied clinical courses caused by malignant clonal proliferation of skin-tropic T cells. Most patients have an indolent disease course managed with skin-directed therapies. In contrast, others, especially in advanced stages of disease or with specific forms, have aggressive progression and poor median survival. Sézary syndrome (SS), a leukemic variant of CTCL, lacks highly consistent phenotypic and genetic markers that may be leveraged to prevent the delay in diagnosis experienced by most patients with CTCL and could be useful for optimal treatment selection. Using single-cell mRNA and T-cell receptor sequencing of peripheral blood immune cells in SS, we extensively mapped the transcriptomic variations of nearly 50 000 T cells of both malignant and nonmalignant origins. We identified potential diverging SS cell populations, including quiescent and proliferative populations shared across multiple patients. In particular, the expression of AIRE was the most highly upregulated gene in our analysis, and AIRE protein expression could be observed over a variety of CTCLs. Furthermore, within a single patient, we were able to characterize differences in cell populations by comparing malignant T cells over the course of treatment with histone deacetylase inhibition and photopheresis. New cellular clusters after progression of the therapy notably exhibited increased expression of the transcriptional factor FOXP3, a master regulator of regulatory T-cell function, raising the potential implication of an evolving mechanism of immune evasion., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Artificial intelligence is generating substantial interest in the field of medicine. One form of artificial intelligence, deep learning, has led to rapid advances in automated image analysis. In 2017, an algorithm demonstrated the ability to diagnose certain skin cancers from clinical photographs with the accuracy of an expert dermatologist. Subsequently, deep learning has been applied to a range of dermatology applications. Although experts will never be replaced by artificial intelligence, it will certainly affect the specialty of dermatology. In this first article of a 2-part series, the basic concepts of deep learning will be reviewed with the goal of laying the groundwork for effective communication between clinicians and technical colleagues. In part 2 of the series, the clinical applications of deep learning in dermatology will be reviewed and limitations and opportunities will be considered., (Copyright © 2020 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Because of a convergence of the availability of large data sets, graphics-specific computer hardware, and important theoretical advancements, artificial intelligence has recently contributed to dramatic progress in medicine. One type of artificial intelligence known as deep learning has been particularly impactful for medical image analysis. Deep learning applications have shown promising results in dermatology and other specialties, including radiology, cardiology, and ophthalmology. The modern clinician will benefit from an understanding of the basic features of deep learning to effectively use new applications and to better gauge their utility and limitations. In this second article of a 2-part series, we review the existing and emerging clinical applications of deep learning in dermatology and discuss future opportunities and limitations. Part 1 of this series offered an introduction to the basic concepts of deep learning to facilitate effective communication between clinicians and technical experts., (Copyright © 2020 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Background: The pathogenesis of pityriasis rubra pilaris (PRP) is not completely understood, but interleukin (IL)-17 has been shown to play a critical role. There are no reliable immunomodulatory agents to treat PRP. We conducted an open-label, single-arm clinical trial of secukinumab, a monoclonal antibody that inhibits IL-17A, for the treatment of PRP., Objectives: To evaluate the clinical efficacy of secukinumab and define the transcriptomic landscape of PRP and its response to IL-17A blockade., Methods: Twelve patients with PRP were recruited for an open-label trial of secukinumab. Patients received a 24-week course of secukinumab. The primary endpoint was a ≥ 75% reduction in Psoriasis Area and Severity Index (PASI 75) from baseline to week 28. Secondary endpoints included PASI 90, change in Physician's Global Assessment (PGA), and change in Dermatology Life Quality Index (DLQI). RNA sequencing was performed on lesional and nonlesional skin biopsies obtained at baseline and week 2. Sample groups were compared to identify differential gene expression and pathway enrichment. This trial was registered with ClinicalTrials.gov: 'Cosentyx (secukinumab) for the treatment of adult onset pityriasis rubra pilaris' - NCT03342573., Results: At week 28, six of 11 patients (55%) achieved PASI 75, and three patients (27%) achieved PASI 90. PGA (P = 0.008) and DLQI scores (P = 0.010) showed significant improvement with treatment. No serious treatment-related adverse events were encountered. Treatment with secukinumab normalized transcriptional differences between lesional and nonlesional skin. Transcriptomic data from nonresponsive patients suggest that overactivity of innate immune pathways may be driving resistance to secukinumab., Conclusions: Secukinumab appears to be an effective treatment for PRP and warrants further investigation. PRP is a transcriptionally heterogeneous disease, reflecting its variable response to therapy. Agents targeting other IL-17 isoforms and innate immune mediators should be considered for future clinical trials. What is already known about this topic? The pathogenesis of pityriasis rubra pilaris is incompletely understood. Successful treatment has been reported with a variety of immunomodulatory agents, but disease is often refractory to therapy. Interleukin (IL)-17 is thought to drive keratinocyte proliferation and vascular dysfunction in this disease. A previous trial demonstrated efficacy of the anti-IL-17A drug ixekizumab for pityriasis rubra pilaris. What does this study add? Herein we describe the findings of a clinical trial of secukinumab, an anti-IL-17A monoclonal antibody, for the treatment of pityriasis rubra pilaris. Secukinumab was effective in treating pityriasis rubra pilaris. Our transcriptomic data give new insight into the expressional changes that occur in response to secukinumab and suggest mechanisms of treatment resistance., (© 2022 British Association of Dermatologists.)

Competing Interests: Conflicts of interest None disclosed.

Importance: There is a knowledge gap about subcutaneous panniculitis-like T-cell lymphoma (SPTCL) owing to its rarity and diagnostic difficulty, resulting in an absence of well-documented large case series published to date., Objective: To generate consensus knowledge by a joint multi-institutional review of SPTCL and related conditions., Design, Setting, and Participants: This retrospective clinical and pathological review included cases initially diagnosed as SPTCL at 6 large US academic centers. All cases were reviewed by a group of pathologists, dermatologists, and oncologists with expertise in cutaneous lymphomas. Through a process of group consensus applying defined clinical and pathological diagnostic criteria, the cohort was classified as (1) SPTCL or (2) adipotropic lymphoproliferative disorder (ALPD) for similar cases with incomplete histopathological criteria for SPTCL designation., Exposures: Cases of SPTCL diagnosed between 1998 and 2018., Main Outcomes and Measures: The main outcome was disease presentation and evolution, including response to therapy, disease progression, and development of hemophagocytic lymphohistiocytosis., Results: The cohort of 95 patients (median [range] age, 38 [2-81] years; female-to-male ratio, 2.7) included 75 cases of SPTCL and 20 cases of ALPD. The clinical presentation was similar for both groups with multiple (61 of 72 [85%]) or single (11 of 72 [15%]) tender nodules mostly involving extremities, occasionally resulting in lipoatrophy. Hemophagocytic lymphohistiocytosis (HLH) was only observed in SPTCL cases. With a mean follow-up of 56 months, 60 of 90 patients (67%) achieved complete remission with a median (range) of 3 (1-7) cumulative therapies. Relapse was common. None of the patients died of disease progression or HLH. Two patients with ALPD eventually progressed to SPTCL without associated systemic symptoms or HLH., Conclusions and Relevance: In this case series of patients initially diagnosed as having SPTCL, results showed no evidence of systemic tumoral progression beyond the adipose tissue. The SPTCL experience in this study confirmed an indolent course and favorable response to a variety of treatments ranging from immune modulation to chemotherapy followed by hematopoietic stem cell transplantation. Morbidity was primarily associated with HLH.

Importance: Given that mycosis fungoides-cutaneous T-cell lymphoma (MF/CTCL) is chronic, there is a need for additional therapies with minimal short- and long-term adverse effects. Topical synthetic hypericin ointment, 0.25%, activated with visible light is a novel, nonmutagenic photodynamic therapy (PDT)., Objectives: To determine the efficacy and safety of topical synthetic hypericin ointment, 0.25%, activated with visible light as a nonmutagenic PDT in early-stage MF/CTCL., Design, Settings, and Participants: This was a multicenter, placebo-controlled, double-blinded, phase 3 randomized clinical trial (FLASH study) conducted from December 2015 to November 2020 at 39 academic and community-based US medical centers. Participants were adults (≥18 years) with early-stage (IA-IIA) MF/CTCL., Interventions: In cycle 1, patients were randomized 2:1 to receive hypericin or placebo to 3 index lesions twice weekly for 6 weeks. In cycle 2, all patients received the active drug for 6 weeks to index lesions. In cycle 3 (optional), both index and additional lesions received active drug for 6 weeks., Main Outcomes and Measures: The primary end point was index lesion response rate (ILRR), defined as 50% or greater improvement in modified Composite Assessment of Index Lesion Severity (mCAILS) score from baseline after 6 weeks of therapy for cycle 1. For cycles 2 and 3, open label response rates were secondary end points. Adverse events (AEs) were assessed at each treatment visit, after each cycle, and then monthly for 6 months. Data analyses were performed on December 21, 2020., Results: The study population comprised 169 patients (mean [SD] age, 58.4 [16.0] years; 96 [57.8%] men; 120 [72.3%] White individuals) with early-stage MF/CTCL. After 6 weeks of treatment, hypericin PDT was more effective than placebo (cycle 1 ILRR, 16% vs 4%; P = .04). The ILRR increased to 40% in patients who received 2 cycles of hypericin PDT (P < .001 vs cycle 1 hypericin) and to 49% after 3 cycles (P < .001 vs cycle 1 hypericin). Significant clinical responses were observed in both patch and plaque type lesions and were similar regardless of age, sex, race, stage IA vs IB, time since diagnosis, and number of prior therapies. The most common treatment-related AEs were mild local skin (13.5%-17.3% across cycles 1-3 vs 10.5% for placebo in cycle 1) and application-site reactions (3.2%-6.9% across cycles 1-3 vs 4% for placebo in cycle 1). No drug-related serious AEs occurred., Conclusion and Relevance: The findings of this randomized clinical trial indicate that synthetic hypericin PDT is effective in early-stage patch and plaque MF/CTCL and has a favorable safety profile., Trial Registration: ClinicalTrials.gov Identifier: NCT02448381.

Background: Necrobiosis lipoidica (NL) is an uncommon granulomatous dermatosis that can occur in patients with or without associated diabetes mellitus (DM). Prior studies have attempted to determine distinctive histopathologic features of NL in patients with and without DM., Methods: A retrospective review of 97 patients with NL was performed to determine the similar and distinctive histopathologic features in patients with DM and without DM., Results: Of the 97 patients, 32% (n = 31) had DM. Epidermal acanthosis was seen more commonly in diabetics than nondiabetics (32.3% vs. 12.1%; p = 0.017). Naked (sarcoidal/tuberculoid) granulomas were more frequently observed in nondiabetics than diabetics (22.7% vs. 3.2%; p = 0.016). Eosinophils were more common in nondiabetics than diabetics (38.5% vs. 9.7%; p = 0.004), while neutrophilic infiltration was more common in diabetics than nondiabetics (45.2% vs. 17.5%; p = 0.004)., Conclusions: This study corroborates well-documented histopathologic features of NL and shows distinctive histopathologic features of NL among patients with DM-I, DM-II, and without DM. These results support the hypothesis that there are different underlying drivers of NL between diabetics and nondiabetics., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Ruxolitinib is a Janus kinase 1/2 inhibitor that blocks signal transduction of interferon-gamma, a critical cytokine involved in the pathogenesis of cutaneous lichen planus (LP). In this prospective phase II study, we investigated the efficacy of topical ruxolitinib in cutaneous LP and performed transcriptomic analysis before and after therapy. Twelve patients with cutaneous LP applied topical ruxolitinib twice daily for 8 weeks. Primary endpoints were changes in total lesion count and changes in modified Composite Assessment of Index Lesion Severity score in index treated and untreated index control lesions at week 4. Total lesion count decreased by a median of 50 lesions (interquartile range 25, 723; P < 0.001). modified Composite Assessment of Index Lesion Severity scores decreased by a mean difference of 7.6 (standard deviation 8.8, P = 0.016) between index treated and control lesions. Type I and II interferon pathways were enriched in LP, and responsive disease displayed downregulation of interferon-stimulated genes. In this small pilot study, topical ruxolitinib was highly effective in the treatment of cutaneous LP. Transcriptomic analysis confirmed LP as an interferon-driven disease and downregulation of interferon-stimulated genes correlated with disease response., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Conflicts of interest None disclosed.

Competing Interests: Conflicts of interest None disclosed.

Competing Interests: Conflicts of interest None disclosed.

Competing Interests: Conflicts of interest Dr Mangold reports personal fees from Kirin and grants from Elorac, MiRagen, Solagenix, DUSA/Sun Pharma, and Acetilion, outside the submitted work. Drs Costello, DiCaudo, Comfere, Sluzevich, Rule, Craig, Rosenthal, and Pittelkow and authors Besch-Stokes, Severson, Bhullar, Montoya, and Butterfield have no conflicts of interest to declare.

Background: Cutaneous squamous cell carcinomas (cSCC) have upstage rates of approximately 10.3% to 11.1%. Data are currently limited on the rate of upstaging for metastatic cSCC., Objective: The aim of this study was to determine the rates of upstaging, between diagnosis and surgery, and differences in management for metastatic and non-metastatic high-risk cSCC., Materials and Methods: This was a retrospective, case-control, single institution, multi-center study. Univariate analysis was used., Results: Sixty-eight subjects (34 metastatic & 34 non-metastatic) with 69 tumors were included. The overall rate of upstaging was 46.4%. The most common reasons for upstage were undocumented tumor size and under-diagnosis of poor differentiation. There were no differences in rates of upstaging. Preoperative imaging was performed in 43.6% of wide local excisions (WLE) versus 3.3% of Mohs micrographic surgery (MMS; p < .001). The median days from surgery to sentinel lymph node biopsy (SLNB), or nodal dissection was shorter for WLE versus MMS (0 vs 221 days, p < .001)., Conclusion: Improved clinical documentation, including documenting tumor size, and the identification of pathologic risk factors, including poor differentiation and depth of invasion, are needed for proper staging. Preoperative imaging and discussion of SLNB may be beneficial for high-risk T2b and T3 tumors., (Copyright © 2021 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. All rights reserved.)