{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,4]],"date-time":"2026-02-04T17:09:37Z","timestamp":1770224977344,"version":"3.49.0"},"reference-count":36,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2026,2,2]],"date-time":"2026-02-02T00:00:00Z","timestamp":1769990400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100005888","name":"Medical University of Lodz","doi-asserted-by":"crossref","award":["500\/1-064-01\/503-11-001"],"award-info":[{"award-number":["500\/1-064-01\/503-11-001"]}],"id":[{"id":"10.13039\/501100005888","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background: Primary cutaneous B-cell lymphomas (CBCLs) are a rare and heterogeneous group of lymphomas, among which the anaplastic variant of diffuse large B-cell lymphoma (A-DLBCL) represents an exceptionally rare entity. Although they typically present as painless and non-ulcerated skin lesions, rare variants may exhibit atypical clinical features. Pyoderma gangrenosum (PG) is a rare inflammatory ulcerative disease that may overlap clinically with other ulcerative dermatoses and pose diagnostic challenges due to the absence of standardized differential algorithms. Methods: An 85-year-old male presented with multiple rapidly progressive, painful, ulcerative lesions, initially misdiagnosed as PG and treated with oral cyclosporine with no clinical response. Skin biopsy specimens underwent detailed histopathological and immunohistochemical evaluation. Results: The analyses revealed dense infiltration of atypical large lymphoid cells, with CD20, CD45, and CD30 positivity, and a Ki-67 proliferation index of approximately 90%, consistent with primary cutaneous A-DLBCL. Owing to the delayed correct diagnosis, the patient\u2019s condition deteriorated rapidly, leading to his death before appropriate therapy could be initiated. Conclusions: The case documents an exceptionally rare cutaneous presentation of A-DLBCL, expanding the extremely limited literature on this enigmatic entity. Furthermore, it underscores the fundamental role of early skin biopsy in the differential diagnosis of non-specific ulcerative lesions, which is critical for ensuring appropriate treatment administration within the therapeutic window in cases of malignancy.<\/jats:p>","DOI":"10.3390\/jcm15031138","type":"journal-article","created":{"date-parts":[[2026,2,2]],"date-time":"2026-02-02T09:00:33Z","timestamp":1770022833000},"page":"1138","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Primary Cutaneous B-Cell Lymphoma Imitating Pyoderma Gangrenosum: A Rare and Complex Diagnostic Challenge"],"prefix":"10.3390","volume":"15","author":[{"given":"Maria","family":"Markowska","sequence":"first","affiliation":[{"name":"Department of Infectious, Tropical and Parasitic Diseases for Children, W\u0142adys\u0142aw Biega\u0144ski Voivodeship Specialist Hospital, Gen. Karola Kniaziewicza Street 1\/5, 91-347 Lodz, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-9095-4880","authenticated-orcid":false,"given":"\u0141ukasz","family":"Ch\u0119tko","sequence":"additional","affiliation":[{"name":"Student Scientific Research Club of Experimental, Clinical and Procedural Dermatology, Medical University of Lodz, Pomorska Street 251, 92-213 Lodz, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Natalia","family":"Bie\u0144","sequence":"additional","affiliation":[{"name":"International Doctoral School, Medical University of Lodz, Hallera 1 Square, 90-647 Lodz, Poland"},{"name":"Department of Dermatology, Pediatric Dermatology and Dermatological Oncology, Medical University of Lodz, Pomorska Street 251, 92-213 Lodz, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Maria","family":"Rajczak","sequence":"additional","affiliation":[{"name":"International Doctoral School, Medical University of Lodz, Hallera 1 Square, 90-647 Lodz, Poland"},{"name":"Department of Dermatology, Pediatric Dermatology and Dermatological Oncology, Medical University of Lodz, Pomorska Street 251, 92-213 Lodz, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9709-3383","authenticated-orcid":false,"given":"Magdalena","family":"Ci\u0105\u017cy\u0144ska","sequence":"additional","affiliation":[{"name":"Department of Dermatology, Pediatric Dermatology and Dermatological Oncology, Medical University of Lodz, Pomorska Street 251, 92-213 Lodz, Poland"},{"name":"Chemotherapy Sub-Department and One-Day Chemotherapy Department, Specialist Oncological Hospital NU-MED sp. z o. o., 97-200 Tomasz\u00f3w Mazowiecki, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Joanna","family":"Narbutt","sequence":"additional","affiliation":[{"name":"Department of Dermatology, Pediatric Dermatology and Dermatological Oncology, Medical University of Lodz, Pomorska Street 251, 92-213 Lodz, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Aleksandra","family":"Lesiak","sequence":"additional","affiliation":[{"name":"Department of Dermatology, Pediatric Dermatology and Dermatological Oncology, Medical University of Lodz, Pomorska Street 251, 92-213 Lodz, Poland"},{"name":"Laboratory of Autoinflammatory, Genetic and Rare Skin Disorders, Medical University of Lodz, Pomorska Street 251, 92-213 Lodz, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Chen, B., Li, W., and Qu, B. (2023). Practical aspects of the diagnosis and management of pyoderma gangrenosum. Front. Med., 10.","DOI":"10.3389\/fmed.2023.1134939"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"461467","DOI":"10.1155\/2014\/461467","article-title":"Pyoderma gangrenosum: A review of clinical features and outcomes of 23 cases requiring inpatient management","volume":"2014","author":"Ye","year":"2014","journal-title":"Dermatol. Res. Pract."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"511","DOI":"10.1007\/s40257-025-00941-z","article-title":"Clinical mimickers misdiagnosed as pyoderma gangrenosum","volume":"26","author":"Becker","year":"2025","journal-title":"Am. J. Clin. Dermatol."},{"key":"ref_4","first-page":"20","article-title":"Atypical ulcers: Wound biopsy results from a university wound pathology service","volume":"58","author":"Tang","year":"2012","journal-title":"Ostomy\/Wound Manag."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"403","DOI":"10.1111\/j.1742-481X.2011.00899.x","article-title":"Prevalence of immune disease in patients with wounds presenting to a tertiary wound healing centre","volume":"9","author":"Shanmugam","year":"2012","journal-title":"Int. Wound J."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Vitiello, P., Sica, A., Ronchi, A., Caccavale, S., Franco, R., and Argenziano, G. (2020). Primary Cutaneous B-Cell Lymphomas: An Update. Front. Oncol., 10.","DOI":"10.3389\/fonc.2020.00651"},{"key":"ref_7","unstructured":"(2025, December 15). Cutaneous B-Cell Lymphoma: Overview, Pathophysiology, Epidemiology. Available online: https:\/\/emedicine.medscape.com\/article\/1099540-overview."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1703","DOI":"10.1182\/blood-2018-11-881268","article-title":"The 2018 update of the WHO-EORTC classification for primary cutaneous lymphomas","volume":"133","author":"Willemze","year":"2019","journal-title":"Blood"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1007\/s12288-019-01096-8","article-title":"Anaplastic Diffuse Large B Cell Lymphoma: A Single Center Experience","volume":"35","author":"Singh","year":"2019","journal-title":"Indian J. Hematol. Blood Transfus."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"251","DOI":"10.1111\/pin.12653","article-title":"Anaplastic variant of diffuse large B-cell lymphoma with hallmark cell appearance: Two cases highlighting a broad diversity in the diagnostics","volume":"68","author":"Sakakibara","year":"2018","journal-title":"Pathol. Int."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"550","DOI":"10.1007\/s12185-010-0675-9","article-title":"CD30-positive anaplastic variant diffuse large B cell lymphoma: A rare case presented with cutaneous involvement","volume":"92","author":"Asano","year":"2010","journal-title":"Int. J. Hematol."},{"key":"ref_12","first-page":"243","article-title":"Primary cutaneous lymphomas\u2014Diagnostic and therapeutic guidelines of the Polish Dermatological Society","volume":"104","author":"Maj","year":"2017","journal-title":"Dermatol. Rev.\/Przegl. Dermatol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1515\/med-2020-0018","article-title":"Primary Cutaneous DLBCL Non-GCB Type: Challenges of a Rare Case","volume":"15","author":"Sica","year":"2020","journal-title":"Open Med. (Wars)"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"718","DOI":"10.1046\/j.1365-4362.2003.01775.x","article-title":"Primary cutaneous CD30-positive large B-cell lymphoma associated with Epstein-Barr virus","volume":"42","author":"Oguz","year":"2003","journal-title":"Int. J. Dermatol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1322","DOI":"10.1097\/PAS.0000000000000836","article-title":"Anaplastic Variant of Diffuse Large B-cell Lymphoma Displays Intricate Genetic Alterations and Distinct Biological Features","volume":"41","author":"Li","year":"2017","journal-title":"Am. J. Surg. Pathol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1007\/s12185-025-03997-z","article-title":"JSH practical guidelines for hematological malignancies, 2023: II. Lymphoma5. Diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS)","volume":"122","author":"Ohmachi","year":"2025","journal-title":"Int. J. Hematol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"460","DOI":"10.1016\/S1470-2045(11)70069-9","article-title":"Attenuated immunochemotherapy regimen (R-miniCHOP) in elderly patients older than 80 years with diffuse large B-cell lymphoma: A multicentre, single-arm, phase 2 trial","volume":"12","author":"Peyrade","year":"2011","journal-title":"Lancet Oncol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1726","DOI":"10.3324\/haematol.2013.090597","article-title":"Rituximab plus gemcitabine and oxaliplatin in patients with refractory\/relapsed diffuse large B-cell lymphoma who are not candidates for high-dose therapy. A phase II Lymphoma Study Association trial","volume":"98","author":"Mounier","year":"2013","journal-title":"Haematologica"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"e328","DOI":"10.1016\/S2352-3026(19)30051-1","article-title":"Anthracycline dose optimisation in patients with diffuse large B-cell lymphoma: A multicentre, phase 3, randomised, controlled trial","volume":"6","author":"Xu","year":"2019","journal-title":"Lancet Haematol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"638","DOI":"10.1002\/hon.2524","article-title":"R-THP-COP versus R-CHOP in patients younger than 70 years with untreated diffuse large B cell lymphoma: A randomized, open-label, noninferiority phase 3 trial","volume":"36","author":"Hara","year":"2018","journal-title":"Hematol. Oncol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"282","DOI":"10.1200\/JCO.2013.49.7586","article-title":"De novo treatment of diffuse large B-cell lymphoma with rituximab, cyclophosphamide, vincristine, gemcitabine, and prednisolone in patients with cardiac comorbidity: A United Kingdom National Cancer Research Institute trial","volume":"32","author":"Fields","year":"2014","journal-title":"J. Clin. Oncol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1083","DOI":"10.3324\/haematol.2022.281407","article-title":"Diffuse large B-cell lymphoma in octogenarians aged 85 and older can benefit from treatment with curative intent: A report on 129 patients prospectively registered in the Elderly Project of the Fondazione Italiana Linfomi (FIL)","volume":"108","author":"Tucci","year":"2023","journal-title":"Haematologica"},{"key":"ref_23","unstructured":"(2026, January 10). Skin Nontumor. Neutrophilic and Eosinophilic Dermatoses. Pyoderma Gangrenosum. Available online: https:\/\/www.pathologyoutlines.com\/topic\/skinnontumorpyodermagangrenosum.html."},{"key":"ref_24","unstructured":"(2026, January 10). Skin Nonmelanocytic Tumor. Lymphoma and Related Disorders. Primary Cutaneous B Cell Lymphoma (PCBCL). Primary Cutaneous Diffuse Large B Cell Lymphoma, Leg Type. Available online: https:\/\/www.pathologyoutlines.com\/topic\/lymphomadiffuselargeBcellleg.html."},{"key":"ref_25","unstructured":"(2026, January 10). Skin Nonmelanocytic Tumor. Lymphoma and Related Disorders. Primary Cutaneous B Cell Lymphoma (PCBCL). Primary Cutaneous Follicle Center Lymphoma. Available online: https:\/\/www.pathologyoutlines.com\/topic\/lymphomafollicularcutaneous.html."},{"key":"ref_26","unstructured":"(2026, January 10). Lymphoma & Related Disorders. Mature B cell Neoplasms. DLBCL and Large B Cell Lymphomas with High Grade Features DLBCL, NOS. Available online: https:\/\/www.pathologyoutlines.com\/topic\/lymphomadiffuse.html."},{"key":"ref_27","unstructured":"(2026, January 10). Lymphoma & Related Disorders. Mature B Cell Neoplasms. Large B Cell Lymphomas-Special Subtypes. EBV+ DLBCL. Available online: https:\/\/www.pathologyoutlines.com\/topic\/lymphomadiffuseEBV.html."},{"key":"ref_28","unstructured":"(2026, January 10). Skin Nonmelanocytic Tumor. Lymphoma and Related Disorders. Cutaneous T Cell Lymphoma (CTCL). Lymphomatoid Papulosis. Available online: https:\/\/www.pathologyoutlines.com\/topic\/skintumornonmelanocyticlymphomatoidpapulosis.html."},{"key":"ref_29","unstructured":"(2026, January 10). Skin Nonmelanocytic Tumor. Lymphoma and Related Disorders. Cutaneous T Cell Lymphoma (CTCL). Primary Cutaneous Anaplastic Large Cell Lymphoma. Available online: https:\/\/www.pathologyoutlines.com\/topic\/skintumornonmelanocyticanaplasticlargecell.html."},{"key":"ref_30","first-page":"43","article-title":"Pyoderma gangrenosum as a possible paraneoplastic disease\u2014Case study and literature review","volume":"110","author":"Gorzkowski","year":"2023","journal-title":"Dermatol. Rev.\/Przegl. Dermatol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1412","DOI":"10.1056\/NEJMoa013383","article-title":"Skin ulcers misdiagnosed as pyoderma gangrenosum","volume":"347","author":"Weenig","year":"2002","journal-title":"N. Engl. J. Med."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1346","DOI":"10.1016\/j.jaad.2019.09.032","article-title":"Pyoderma gangrenosum in hematologic malignancies: A systematic review","volume":"82","author":"Montagnon","year":"2020","journal-title":"J. Am. Acad. Dermatol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"615","DOI":"10.1111\/bjd.16401","article-title":"The PARACELSUS score: A novel diagnostic tool for pyoderma gangrenosum","volume":"180","author":"Wollina","year":"2019","journal-title":"Br. J. Dermatol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"461","DOI":"10.1001\/jamadermatol.2017.5980","article-title":"Diagnostic Criteria of Ulcerative Pyoderma Gangrenosum: A Delphi Consensus of International Experts","volume":"154","author":"Maverakis","year":"2018","journal-title":"JAMA Dermatol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"e1052","DOI":"10.1111\/jdv.20861","article-title":"Large language models in evaluating hidradenitis suppurativa from clinical images","volume":"39","author":"Boostani","year":"2025","journal-title":"J. Eur. Acad. Dermatol. Venereol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1881","DOI":"10.1111\/ijd.17729","article-title":"Diagnostic Performance of GPT-4o and Gemini Flash 2.0 in Acne and Rosacea","volume":"64","author":"Boostani","year":"2025","journal-title":"Int. J. Dermatol."}],"container-title":["Journal of Clinical Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/3\/1138\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,4]],"date-time":"2026-02-04T05:17:12Z","timestamp":1770182232000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/3\/1138"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,2]]},"references-count":36,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2026,2]]}},"alternative-id":["jcm15031138"],"URL":"https:\/\/doi.org\/10.3390\/jcm15031138","relation":{},"ISSN":["2077-0383"],"issn-type":[{"value":"2077-0383","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,2]]}}}