A 41-year-old man presented with history of paresthesia, weakness in the legs to the point of not being able to walk, constipation and urinary retention for the last 6 months. For the previous 18 months he got deep depressed and lost 36kg after his wife died of breast cancer. Physical examination was marked by psychomotor slowing, paresis over four members, especially legs, a sensitive level on T11 and impairment of proprioception. Laboratory analysis revealed pancytopenia, macrocytosis low vitamin B12 level and high homocysteine. He had no diet restrictions. Tests for syphilis were negative. Serology for celiac disease and antibody to intrinsic factor and parietal cells were negative.
