[Hypervitaminosis B12. Our experience and a review].

High serum levels of vitamin B12 or cobalamin, also called hypervitaminemia B12, is a frequently underestimated biological abnormality. According to the literature, some of the entities related to this finding are solid neoplasia (primary or metastatic) and acute or chronic hematological diseases. Other causes include liver disorders, monoclonal gammapathy of undetermined significance, renal failure and, less frequently, excess of vitamin B12 intake, inflammatory or autoimmune diseases, and transient hematological disorders (neutrophilia and secondary eosinophilia). This article reports on causes of hypervitaminosis B12, our experience and a review of the literature.