The vulnerable esophagus: riboflavin deficiency and squamous cell dysplasia of the skin and the esophagus.

Eleven male baboons fed a synthetic diet completely lacking in riboflavin developed, after 15-36 weeks, profound macroscopic and microscopic architectural disorganization of the skin, mouth, and esophagus. The cutaneous lesions showed hyperkeratosis, gross derangement of keratinization with acanthosis, and impressive pseudocarcinomatous hyperplasia. In 5 baboons that died or were killed, there were large penetrating lesions having raised epithelial edges at the lower third of the esophagus or at the cardioesophageal junction, with gross epithelial hyperplasia and grossly deranged and thickened keratinization and numerous mitotic figures. None of the 8 control animals given riboflavin showed these abnormalities.