{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,15]],"date-time":"2026-04-15T14:02:40Z","timestamp":1776261760644,"version":"3.50.1"},"reference-count":14,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2026,4,15]],"date-time":"2026-04-15T00:00:00Z","timestamp":1776211200000},"content-version":"vor","delay-in-days":104,"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"}],"funder":[{"DOI":"10.13039\/100018234","name":"Inselspital, Universit\u00e4tsspital Bern","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100018234","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Case Reports in Hematology"],"published-print":{"date-parts":[[2026,1]]},"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Vitamin B12 deficiency can cause severe intramedullary hemolysis and cytopenias. Myeloproliferative neoplasms (MPNs), particularly polycythemia vera (PV), are typically characterized by hyperproliferation but may remain undetected when masked by concomitant deficiencies.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Case Presentation<\/jats:title>\n                    <jats:p>A 48\u2010year\u2010old woman presented with fatigue, weight loss, and pancytopenia. Laboratory tests showed severe macrocytic anemia, hemolysis, and markedly reduced vitamin B12 levels. Gastroscopy and antibody testing confirmed autoimmune atrophic gastritis with pernicious anemia. Bone marrow biopsy revealed hypercellularity, panmyelosis, and myelofibrosis (MF\u20102), initially interpreted as reactive. After vitamin B12 supplementation, cytopenias resolved; however, follow\u2010up demonstrated polycythemia, leukocytosis, and thrombocytosis. Molecular analysis identified a JAK2 V617F mutation (variant allele fraction 40%), confirming PV with progression toward myelofibrosis. The patient was treated with phlebotomy, low\u2010dose aspirin, and hydroxyurea, alongside continued vitamin B12 replacement. In addition, mild alpha\u2010thalassemia was diagnosed in the course of an increasingly microcytic hypochromic blood count.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Severe vitamin B12 deficiency may mask an underlying MPN, as well as other hematologic disorders like alpha\u2010thalassemia. Close follow\u2010up after hematologic recovery is essential to avoid delayed diagnosis of coexisting hematologic malignancies and disorders. This case presents a combination of complex and extremely rare hematological scenarios, where various hematological disorders exert conflicting influences on red blood cell indices, making diagnosis challenging.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1155\/crh\/8353795","type":"journal-article","created":{"date-parts":[[2026,4,15]],"date-time":"2026-04-15T13:08:55Z","timestamp":1776258535000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Pernicious Anemia Resulting in Intramedullary Hemolysis, Masking Underlying Polycythemia Vera and Mild Alpha\u2010Thalassemia\u2014A Case Report"],"prefix":"10.1155","volume":"2026","author":[{"given":"Amanda","family":"Rohner","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7716-3340","authenticated-orcid":false,"given":"Annatina Sarah","family":"Schnegg-Kaufmann","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4474-3132","authenticated-orcid":false,"given":"Yara","family":"Banz","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-1852-8577","authenticated-orcid":false,"given":"Piet","family":"Rosenstock","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2026,4,15]]},"reference":[{"key":"e_1_2_9_1_2","doi-asserted-by":"publisher","DOI":"10.3945\/ajcn.2008.26947A"},{"key":"e_1_2_9_2_2","doi-asserted-by":"publisher","DOI":"10.1093\/qjmed\/hct142"},{"key":"e_1_2_9_3_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.amjmed.2006.02.001"},{"key":"e_1_2_9_4_2","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.nutr.24.012003.132306"},{"key":"e_1_2_9_5_2","doi-asserted-by":"publisher","DOI":"10.1016\/s0950-3536(05)80215-x"},{"key":"e_1_2_9_6_2","doi-asserted-by":"publisher","DOI":"10.7861\/clinmedicine.15-2-145"},{"key":"e_1_2_9_7_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41375-022-01613-1"},{"key":"e_1_2_9_8_2","doi-asserted-by":"publisher","DOI":"10.1177\/003591577006300629"},{"key":"e_1_2_9_9_2","doi-asserted-by":"publisher","DOI":"10.1177\/003693306400901102"},{"key":"e_1_2_9_10_2","doi-asserted-by":"publisher","DOI":"10.1136\/pgmj.34.398.638"},{"key":"e_1_2_9_11_2","first-page":"1487","article-title":"Megaloblastic Anemia due to Folic Acid Deficiency in Polycythemia Vera","volume":"97","author":"Whittemore N. 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