Oral epithelial dysplasia in vitamin B12 deficiency

Widespread soreness and focal ulceration of the oral mucosa developed in a woman with vitamin B12 deficiency shortly after hydroxocobalamin therapy had commenced. An oral mucosal biopsy showed disordered epithelial maturation with marked cytologic atypia. However, during the next month of treatment, the patient's oral mucosa became clinically and histologically normal. Pathologists should be aware that vitamin B12 deficiency may be associated with epithelial changes similar to those associated with premalignancy.