Giant axonal neuropathy: possibly secondary to vitamin b12 malabsorption.

A giant axonal neuropathy is described in an adult with no evidence of a childhood onset of his disease and no history of exposure to toxic hydrocarbons. A causal relation to vitamin B12 malabsorption is proposed. This case suggests the need to expand the spectrum of diagnoses that must be considered when giant axons are encountered in peripheral nerve biopsy specimens.