{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,4]],"date-time":"2026-06-04T20:39:45Z","timestamp":1780605585658,"version":"3.54.1"},"reference-count":13,"publisher":"Wiley","issue":"11","license":[{"start":{"date-parts":[[2025,7,24]],"date-time":"2025-07-24T00:00:00Z","timestamp":1753315200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["J Cutan Pathol"],"published-print":{"date-parts":[[2025,11]]},"abstract":"<jats:title>ABSTRACT<\/jats:title><jats:p>Immune checkpoint inhibitors (ICIs) targeting programmed cell death protein 1 (PD\u20101), programmed cell death ligand 1 (PD\u2010L1), and cytotoxic lymphocyte\u2010associated antigen\u20104 (CTLA\u20104) have revolutionized cancer treatment but are associated with immune\u2010related adverse events, particularly cutaneous toxicities. We report a rare case of pembrolizumab\u2010exacerbated pigmented purpuric dermatosis (PPD) in a 77\u2010year\u2010old male with a history of metastatic non\u2010small cell lung cancer. His rash, initially confined to the lower extremities, worsened and became widespread to involve the trunk after pembrolizumab initiation. Histopathology showed perivascular lymphocytic infiltrate with extravasated erythrocytes without vasculitis, compatible with PPD; however, due to some lymphocyte atypia and exocytosis, together with the clinically widespread lesions, there was initial concern for PPD\u2010like mycosis fungoides (MF). Subsequent T\u2010cell receptor gene rearrangement studies revealed no monoclonal lymphoid population, and the later resolution of the rash with treatments typical for PPD did not support MF. This represents only the second reported case of ICI\u2010associated PPD and highlights a potential diagnostic pitfall with histopathology and clinical presentation mimicking PPD\u2010like MF. Our case contributes to the expanding spectrum of ICI\u2010related cutaneous reactions and underscores the importance of recognizing inflammatory dermatoses with atypical histopathologic features for dermatologists and dermatopathologists.<\/jats:p>","DOI":"10.1111\/cup.14841","type":"journal-article","created":{"date-parts":[[2025,7,25]],"date-time":"2025-07-25T02:54:52Z","timestamp":1753412092000},"page":"676-680","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Pembrolizumab\u2010Exacerbated Widespread Pigmented Purpuric Dermatosis in an Elderly Patient, a Potential Diagnostic Pitfall Mimicking Pigmented Purpuric Dermatosis\u2010Like Mycosis Fungoides"],"prefix":"10.1111","volume":"52","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-1542-1652","authenticated-orcid":false,"given":"Nicole","family":"Chang","sequence":"first","affiliation":[{"name":"University of Illinois College of Medicine  Chicago Illinois USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yoni","family":"Hirsch","sequence":"additional","affiliation":[{"name":"Department of Dermatology University of Illinois College of Medicine  Chicago Illinois USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7739-5085","authenticated-orcid":false,"given":"Krisztian","family":"Nemeth","sequence":"additional","affiliation":[{"name":"ProHealth Care  Waukesha Wisconsin USA"},{"name":"Department of Dermatology, Venerology and Dermatooncology Semmelweis University  Budapest Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Susan","family":"Pei","sequence":"additional","affiliation":[{"name":"Department of Dermatology University of Illinois College of Medicine  Chicago Illinois USA"},{"name":"Great Lakes Pathologists SC  West Allis Wisconsin USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2025,7,24]]},"reference":[{"key":"e_1_2_8_2_1","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2014.59.4358"},{"key":"e_1_2_8_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.humpath.2023.04.016"},{"key":"e_1_2_8_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jaad.2020.03.132"},{"key":"e_1_2_8_5_1","doi-asserted-by":"publisher","DOI":"10.1111\/cup.13118"},{"key":"e_1_2_8_6_1","doi-asserted-by":"publisher","DOI":"10.1046\/j.1468\u20103083.2001.00198.x"},{"key":"e_1_2_8_7_1","doi-asserted-by":"publisher","DOI":"10.1111\/cup.13949"},{"key":"e_1_2_8_8_1","doi-asserted-by":"publisher","DOI":"10.4103\/2229\u20105178.182361"},{"key":"e_1_2_8_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jdcr.2023.02.008"},{"key":"e_1_2_8_10_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1525\u20101470.2006.00259.x"},{"key":"e_1_2_8_11_1","doi-asserted-by":"publisher","DOI":"10.1097\/CMR.0000000000000664"},{"key":"e_1_2_8_12_1","doi-asserted-by":"publisher","DOI":"10.1111\/cup.13536"},{"key":"e_1_2_8_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jdcr.2018.01.016"},{"key":"e_1_2_8_14_1","doi-asserted-by":"publisher","DOI":"10.5732\/cjc.010.10344"}],"container-title":["Journal of Cutaneous Pathology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/cup.14841","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T04:23:03Z","timestamp":1760329383000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/cup.14841"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,7,24]]},"references-count":13,"journal-issue":{"issue":"11","published-print":{"date-parts":[[2025,11]]}},"alternative-id":["10.1111\/cup.14841"],"URL":"https:\/\/doi.org\/10.1111\/cup.14841","archive":["Portico"],"relation":{},"ISSN":["0303-6987","1600-0560"],"issn-type":[{"value":"0303-6987","type":"print"},{"value":"1600-0560","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,7,24]]},"assertion":[{"value":"2025-04-15","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-07-07","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-07-24","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}