{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T15:51:19Z","timestamp":1782489079611,"version":"3.54.5"},"reference-count":28,"publisher":"BMJ","issue":"4","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2026,4,6]]},"published-print":{"date-parts":[[2026,4]]},"abstract":"<jats:p>A man in his 60s with metastatic lung adenocarcinoma receiving carboplatin, pemetrexed and pembrolizumab presented with subacute bilateral lower limb oedema and erythema. After hospital admission for investigation and treatment with intravenous flucloxacillin, the symptoms did not initially improve. Having considered the broad differential diagnoses, we suspected a rare and poorly understood phenomenon: pseudocellulitis secondary to pemetrexed. Pemetrexed is a chemotherapy used in non-small cell lung cancer that targets enzymes involved in DNA\/RNA synthesis. Subsequently, pemetrexed was withheld and treatment with carboplatin and pembrolizumab continued, following which symptoms improved. Pemetrexed-related pseudocellulitis is an important diagnosis to recognise as it can mimic several conditions, and early recognition may help minimise hospital admissions and reduce morbidity. This case highlights the importance of considering a broad range of differential diagnoses in the assessment of bilateral lower leg erythema, which is increasingly complex in the era of combined chemotherapy and immunotherapy treatments.<\/jats:p>","DOI":"10.1136\/bcr-2025-269581","type":"journal-article","created":{"date-parts":[[2026,4,24]],"date-time":"2026-04-24T14:30:23Z","timestamp":1777041023000},"page":"e269581","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":1,"title":["Pseudocellulitis in a patient with non-small cell lung cancer on carboplatin, pemetrexed and pembrolizumab"],"prefix":"10.1136","volume":"19","author":[{"given":"Thomas","family":"Beadman","sequence":"first","affiliation":[{"name":"Medical Oncology, Central Coast Local Health District, Gosford, New South Wales, Australia"},{"name":"Medical Oncology, Nottingham University Hospitals NHS Trust, Nottingham, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6759-6935","authenticated-orcid":false,"given":"Matthew MK","family":"Chan","sequence":"additional","affiliation":[{"name":"Medical Oncology, Central Coast Local Health District, Gosford, New South Wales, Australia"},{"name":"School of Medicine and Public Health, University of Newcastle Medical Society, Newcastle, New South Wales, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,4,24]]},"reference":[{"key":"2026062608154362000_19.4.e269581.1","unstructured":"World Health Organization: WHO . Global cancer burden growing, amidst mounting need for services. World Health Organisation; 2024. Available: https:\/\/www.who.int\/news\/item\/01-02-2024-global-cancer-burden-growing--amidst-mounting-need-for-services"},{"key":"2026062608154362000_19.4.e269581.2","unstructured":"Dubin S , Griffin D . Lung cancer in Non-Smokers. Mo Med 2020;375\u20139. Available: https:\/\/pubmed.ncbi.nlm.nih.gov\/32848276\/"},{"key":"2026062608154362000_19.4.e269581.3","unstructured":"Targeting mutations that drive lung cancer. Nature. Available: https:\/\/www.nature.com\/articles\/d42473-020-00479-0 [Accessed 7 Mar 2025]."},{"key":"2026062608154362000_19.4.e269581.4","unstructured":"Myers DJ , Wallen JM . Lung adenocarcinoma. StatPearls Publishing; 2025. Available: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK519578\/"},{"key":"2026062608154362000_19.4.e269581.5","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa1606774"},{"key":"2026062608154362000_19.4.e269581.6","unstructured":"Flynn JP , Gerriets V . Pembrolizumab. StatPearls Publishing, 2023. Available: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK546616\/"},{"key":"2026062608154362000_19.4.e269581.7","unstructured":"Ramos Morales I , Yacobucci MJ , Sheehy C . Pemetrexed. StatPearls Publishing, 2025. Available: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK606090\/"},{"key":"2026062608154362000_19.4.e269581.8","doi-asserted-by":"publisher","DOI":"10.7150\/thno.69424"},{"key":"2026062608154362000_19.4.e269581.9","unstructured":"Nottingham CityCare Infection Prevention and Control and Tissue Viability Teams . Guidance for the assessment and management of lower limb inflammation (commonly known as red legs). Nottingham CityCare Infection Prevention and Control and Tissue Viability Teams; 2022. Available: https:\/\/www.nottsapc.nhs.uk\/media\/d5nbivyx\/1-guidance-for-inflamed-lower-limbs-v20.pdf"},{"key":"2026062608154362000_19.4.e269581.10","unstructured":"Osti M , Nixon R . Lipodermatosclerosis. 2018. Available: https:\/\/dermnetnz.org\/topics\/lipodermatosclerosis"},{"key":"2026062608154362000_19.4.e269581.11","doi-asserted-by":"publisher","DOI":"10.3949\/ccjm.79a.11121"},{"key":"2026062608154362000_19.4.e269581.12","unstructured":"Ngan V , Mitchell G . Eosinophilic fasciitis. 2021. Available: https:\/\/dermnetnz.org\/topics\/eosinophilic-fasciitis"},{"key":"2026062608154362000_19.4.e269581.13","doi-asserted-by":"crossref","first-page":"444","DOI":"10.4103\/singaporemedj.SMJ-2021-142","article-title":"Approach to bilateral lower limb oedema","volume":"64","author":"Jacob","year":"2023","journal-title":"Singapore Med J"},{"key":"2026062608154362000_19.4.e269581.14","unstructured":"Juan NL , Laura DR , Ethan C . Evaluation of peripheral edema - differential diagnosis of symptoms | BMJ Best Practice Us. Available: https:\/\/bestpractice.bmj.com\/topics\/en-gb\/609 [Accessed 7 Mar 2025]."},{"key":"2026062608154362000_19.4.e269581.15","unstructured":"Elwell R . RED legs pathway. 2020. Available: https:\/\/www.thebls.com\/public\/uploads\/documents\/document-40881639738634.pdf"},{"key":"2026062608154362000_19.4.e269581.16","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2012.47.1102"},{"key":"2026062608154362000_19.4.e269581.17","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa1801005"},{"key":"2026062608154362000_19.4.e269581.18","doi-asserted-by":"crossref","first-page":"1432","DOI":"10.1016\/S0140-6736(09)61497-5","article-title":"Maintenance pemetrexed plus best supportive care versus placebo plus best supportive care for non-small-cell lung cancer: a randomised, double-blind, phase 3 study","volume":"374","author":"Ciuleanu","year":"2009","journal-title":"The Lancet"},{"key":"2026062608154362000_19.4.e269581.19","unstructured":"EviQ . Non small cell lung cancer metastatic pemetrexed. 2018. Available: https:\/\/www.eviq.org.au\/medical-oncology\/respiratory\/non-small-cell-lung-cancer-advanced-metastatic\/236-nsclc-metastatic-pemetrexed#clinical-information"},{"key":"2026062608154362000_19.4.e269581.20","doi-asserted-by":"crossref","unstructured":"Horton LA , Lyons AB , Kwa MC , et al . Pemetrexed-Induced Pseudocellulitis: A Diagnostic Conundrum. Cureus 2024. doi:10.7759\/cureus.52114","DOI":"10.7759\/cureus.52114"},{"key":"2026062608154362000_19.4.e269581.21","doi-asserted-by":"crossref","first-page":"953","DOI":"10.1002\/kjm2.12267","article-title":"Pemetrexed\u2010induced pseudocellulitis","volume":"36","author":"Lo","year":"2020","journal-title":"The Kaohsiung J of Med Scie"},{"key":"2026062608154362000_19.4.e269581.22","doi-asserted-by":"crossref","first-page":"1964","DOI":"10.1097\/JTO.0b013e3182333f34","article-title":"Peripheral Skin Edema as Unusual Toxicity in Three Patients with Advanced Non-small Cell Lung Cancer Treated with Pemetrexed Alone or in Combination with Cisplatin","volume":"6","author":"Galetta","year":"2011","journal-title":"J Thorac Oncol"},{"key":"2026062608154362000_19.4.e269581.23","doi-asserted-by":"publisher","DOI":"10.1097\/JTO.0b013e318207f788"},{"key":"2026062608154362000_19.4.e269581.24","doi-asserted-by":"crossref","first-page":"64","DOI":"10.1016\/j.jdcr.2016.11.001","article-title":"Pemetrexed-induced eccrine squamous syringometaplasia manifesting as pseudocellulitis (in a patient with non-small cell lung cancer)","volume":"3","author":"Santosa","year":"2017","journal-title":"JAAD Case Rep"},{"key":"2026062608154362000_19.4.e269581.25","doi-asserted-by":"crossref","first-page":"e1","DOI":"10.1097\/DAD.0000000000000645","article-title":"Pemetrexed-Induced Pseudocellulitis Reaction With Eosinophilic Infiltrate on Skin Biopsy","volume":"39","author":"Tracey","year":"2017","journal-title":"Am J Dermatopathol"},{"key":"2026062608154362000_19.4.e269581.26","first-page":"769","article-title":"Revisiting cutaneous adverse reactions to pemetrexed","volume":"Available from","author":"Pi\u00ef\u00bf\u00bdrard","year":"2011","journal-title":"Oncol Lett"},{"key":"2026062608154362000_19.4.e269581.27","doi-asserted-by":"publisher","DOI":"10.1684\/ejd.2016.2833"},{"key":"2026062608154362000_19.4.e269581.28","doi-asserted-by":"crossref","DOI":"10.1038\/s41598-022-24286-3","article-title":"Cutaneous adverse events in patients treated with PD-1\/PD-L1 checkpoint inhibitors and their association with survival: a systematic review and meta-analysis","volume":"12","author":"Zhao","year":"2022","journal-title":"Sci Rep"}],"container-title":["BMJ Case Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bcr-2025-269581","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T15:21:49Z","timestamp":1782487309000},"score":1,"resource":{"primary":{"URL":"https:\/\/casereports.bmj.com\/lookup\/doi\/10.1136\/bcr-2025-269581"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4]]},"references-count":28,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2026,4,24]]},"published-print":{"date-parts":[[2026,4]]}},"alternative-id":["10.1136\/bcr-2025-269581"],"URL":"https:\/\/doi.org\/10.1136\/bcr-2025-269581","relation":{},"ISSN":["1757-790X"],"issn-type":[{"value":"1757-790X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4]]}}}