{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T08:17:41Z","timestamp":1787732261645,"version":"build-2784847793"},"reference-count":22,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T00:00:00Z","timestamp":1787702400000},"content-version":"vor","delay-in-days":237,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,1,1]],"date-time":"2026-01-01T00:00:00Z","timestamp":1767225600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Case Reports in Medicine"],"published-print":{"date-parts":[[2026,1]]},"abstract":"<jats:p>The synchronous coexistence of JAK2 V617F\u2010positive essential thrombocythemia (ET) and IgG kappa multiple myeloma (MM) is exceptionally rare, with fewer than 10 synchronous cases reported in the literature. The present case is unique in that MM was discovered incidentally during systematic bone marrow evaluation for isolated thrombocytosis in an octogenarian with significant comorbidities, requiring the concurrent management of two independent clonal hematological neoplasms. An 81\u2010year\u2010old woman with prior hypertension and cerebrovascular disease was referred for persistent thrombocytosis exceeding 1,000,000 platelets\/\u03bcL. Systematic bone marrow evaluation led to the incidental identification of a monoclonal kappa plasma cell population, prompting full myeloma workup. JAK2 V617F\u2010positive high\u2010risk ET and IgG kappa MM (ISS Stage II) were diagnosed synchronously. Acquired von Willebrand syndrome was excluded prior to any anticoagulation decision. Treatment included hydroxyurea\u2014subsequently switched to anagrelide due to a national drug supply shortage\u2014for ET cytoreduction, and a bortezomib\u2013dexamethasone\u2013lenalidomide (VRD) regimen for MM. An IMWG partial response was achieved after three cycles, with adequate platelet control at 8\u2009months of follow\u2010up. This case underscores the importance of systematic bone marrow evaluation in myeloproliferative neoplasms, as it may unmask concurrent plasma cell dyscrasias. Several pathophysiological mechanisms\u2014including IL\u20106\u2010mediated microenvironmental activation, BAFF\u2010driven B\u2010cell proliferation, and a shared inflammatory niche\u2014have been proposed in the literature to explain this co\u2010occurrence; however, these were not directly evaluated in this patient. The regimen chosen was guided by clinical complexity and resource constraints rather than current preferred first\u2010line guidelines, which favor daratumumab\u2010based combinations for transplant\u2010ineligible patients. Early identification of coexisting clonal neoplasms substantially impacts prognosis and therapeutic decision\u2010making.<\/jats:p>","DOI":"10.1155\/carm\/8986847","type":"journal-article","created":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T07:21:17Z","timestamp":1787728877000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Synchronous Coexistence of JAK2 V617F\u2010Positive Essential Thrombocythemia and IgG Kappa Multiple Myeloma in an Octogenarian Patient: A Case Report"],"prefix":"10.1155","volume":"2026","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1902-6273","authenticated-orcid":false,"given":"Marcel","family":"Ribero-Vargas","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8144-8573","authenticated-orcid":false,"given":"Fabi\u00e1n","family":"Ahumada-C\u00f3rdoba","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-7111-4834","authenticated-orcid":false,"given":"Nhora Mar\u00eda","family":"Silva-P\u00e9rez","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5402-4599","authenticated-orcid":false,"given":"Daniel","family":"Ribero-Vargas","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,8,26]]},"reference":[{"key":"e_1_2_10_1_2","doi-asserted-by":"publisher","DOI":"10.3109\/10428194.2015.1071490"},{"key":"e_1_2_10_2_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.clml.2013.09.015"},{"key":"e_1_2_10_3_2","doi-asserted-by":"publisher","DOI":"10.1002\/cam4.5592"},{"key":"e_1_2_10_4_2","doi-asserted-by":"publisher","DOI":"10.3389\/fonc.2023.1213942"},{"key":"e_1_2_10_5_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.cpt.2023.12.001"},{"key":"e_1_2_10_6_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.thromres.2023.11.021"},{"key":"e_1_2_10_7_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41408-020-0289-2"},{"key":"e_1_2_10_8_2","doi-asserted-by":"crossref","DOI":"10.1016\/j.rpth.2025.102954","article-title":"Thrombocytosis and Bleeding in Myeloproliferative Neoplasms: Exploring Clinical Diversity and Risk of Acquired Von Willebrand Syndrome","volume":"9","author":"Simini G.","year":"2025","journal-title":"Research and Practice in Thrombosis and Haemostasis"},{"key":"e_1_2_10_9_2","doi-asserted-by":"publisher","DOI":"10.1038\/leu.2008.291"},{"key":"e_1_2_10_10_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.0954-6820.1977.tb15692.x"},{"key":"e_1_2_10_11_2","article-title":"Essential Thrombocythaemia and Bence Jones Myeloma","volume":"289","author":"Ghosh P.","year":"1984","journal-title":"British Medical Journal"},{"key":"e_1_2_10_12_2","doi-asserted-by":"publisher","DOI":"10.1159\/000187645"},{"key":"e_1_2_10_13_2","doi-asserted-by":"publisher","DOI":"10.1038\/bmt.2010.157"},{"key":"e_1_2_10_14_2","doi-asserted-by":"publisher","DOI":"10.7759\/cureus.4286"},{"key":"e_1_2_10_15_2","doi-asserted-by":"publisher","DOI":"10.7759\/cureus.52622"},{"key":"e_1_2_10_16_2","doi-asserted-by":"publisher","DOI":"10.4103\/ijpm.ijpm_990_23"},{"key":"e_1_2_10_17_2","first-page":"657","article-title":"Increased Levels of Plasma Interleukin-6 Soluble Receptor in Patients With Essential Thrombocythemia","volume":"89","author":"Marta R. 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