{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,24]],"date-time":"2026-04-24T17:42:50Z","timestamp":1777052570834,"version":"3.51.4"},"reference-count":10,"publisher":"BMJ","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Reports"],"accepted":{"date-parts":[[2015,4,29]]},"abstract":"<jats:p>A 15-year-old boy on a vegetarian diet presented with severe macrocytic anaemia (haemoglobin, 5.1\u2005g\/dL; mean corpuscular volume, 116\u2005fL) in addition to leucopenia and thrombocytopaenia (pancytopenia), icterus secondary to haemolysis and splenomegaly. Laboratory investigations revealed severe vitamin B<jats:sub>12<\/jats:sub>(cobalamin) deficiency. Following cobalamin replacement therapy, the patient reported increased well-being, including appetite and weight gain, and his icterus resolved. In the follow-up laboratory examinations, leucocyte and platelet counts in addition to serum bilirubin and lactate dehydrogenase levels normalised. At the end of 2\u2005months, laboratory findings, including haemoglobin level, were all within the normal range. We present this case as a reminder that severe vitamin B<jats:sub>12<\/jats:sub>deficiency may present with findings mimicking acute leukaemia (pancytopenia and splenomegaly) and findings suggestive of pseudothrombotic microangiopathy.<\/jats:p>","DOI":"10.1136\/bcr-2015-209718","type":"journal-article","created":{"date-parts":[[2015,5,14]],"date-time":"2015-05-14T14:54:52Z","timestamp":1431615292000},"page":"bcr2015209718","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":16,"title":["Severe vitamin B<sub>12<\/sub>deficiency in a 15-year-old boy: presentation with haemolysis and pancytopenia"],"prefix":"10.1136","volume":"2015","author":[{"given":"Ebru Y\u0131lmaz","family":"Keskin","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mahmut","family":"Keskin","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2015,5,14]]},"reference":[{"key":"2025042706185665000_2015.may14_1.bcr2015209718.1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMcp1113996"},{"key":"2025042706185665000_2015.may14_1.bcr2015209718.2","doi-asserted-by":"publisher","DOI":"10.3945\/ajcn.2008.26947A"},{"key":"2025042706185665000_2015.may14_1.bcr2015209718.3","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2257.2006.00755.x"},{"key":"2025042706185665000_2015.may14_1.bcr2015209718.4","doi-asserted-by":"publisher","DOI":"10.1111\/jpc.12619"},{"key":"2025042706185665000_2015.may14_1.bcr2015209718.5","doi-asserted-by":"publisher","DOI":"10.1093\/qjmed\/hct142"},{"key":"2025042706185665000_2015.may14_1.bcr2015209718.6","doi-asserted-by":"publisher","DOI":"10.1006\/bbrc.1996.1449"},{"key":"2025042706185665000_2015.may14_1.bcr2015209718.7","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1016\/j.bbadis.2004.08.005","article-title":"A role for homocysteine increase in haemolysis of megaloblastic anemias due to vitamin B12 and folate deficiency: results from an in vitro experience","volume":"1739","author":"Ventura","year":"2004","journal-title":"Biochim Biophys Acta"},{"key":"2025042706185665000_2015.may14_1.bcr2015209718.8","doi-asserted-by":"publisher","DOI":"10.1136\/bcr-2014-203742"},{"key":"2025042706185665000_2015.may14_1.bcr2015209718.9","doi-asserted-by":"publisher","DOI":"10.1080\/08880010802016789"},{"key":"2025042706185665000_2015.may14_1.bcr2015209718.10","doi-asserted-by":"publisher","DOI":"10.1093\/tropej\/fmp039"}],"container-title":["BMJ Case Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bcr-2015-209718","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,4,27]],"date-time":"2025-04-27T13:19:01Z","timestamp":1745759941000},"score":1,"resource":{"primary":{"URL":"https:\/\/casereports.bmj.com\/lookup\/doi\/10.1136\/bcr-2015-209718"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,5,14]]},"references-count":10,"alternative-id":["10.1136\/bcr-2015-209718"],"URL":"https:\/\/doi.org\/10.1136\/bcr-2015-209718","relation":{},"ISSN":["1757-790X"],"issn-type":[{"value":"1757-790X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2015,5,14]]}}}