Acquired Selective Vitamin B₁₂ Malabsorption

Abstract

A 44‐year‐old woman underwent extirpation of a reticulum cell sarcoma in the right anxilla 10 years previously, followed by local roentgen treatment. Subsequently, the patient was irradiated because of enlarged lymph nodes in the left axilla and in the abdomen. Because of megalocytic anaemia and normal serum iron, the patient was given three injections of liver extract, whereupon the haemoglobin values rose to normal levels. An impaired absorption of vitamin B12 was demonstrated which did not improve on intrinsic factor. Otherwise, no hitherto known causes of the reduced vitamin B12 absorption could be found, in particular no other malabsorption symptoms were present. When normal intestinal juice was given concurrently, vitamin B12 was absorbed normally, which indicates that the patient lacks a factor in her intestinal juice which is of importance for a normal absorption of vitamin B12. The underlying mechanism of the biochemical defect in the vitamin B12 absorption is difcussed.