Foveolar hyperplasia secondary to cow's milk protein hypersensitivity presenting with clinical features of pyloric stenosis.

Pyloric stenosis is one of several causes of infantile nonbilious vomiting. A 7-week-old boy presenting with symptoms suggestive of this was found to have a prepyloric lobular mass causing near-complete gastric outlet obstruction. The histology showed localized hypertrophic gastropathy with hyperplasia and tortuosity of foveolar cells reminiscent of Menetrier changes. Postsurgical excision, the child continued vomiting until removal of bovine and soy proteins from his diet. The clinical presentation, pathology, and response to restrictive diet suggested cow's milk protein allergy as key. The literature describing infantile focal foveolar hyperplasia and Menetrier disease is reviewed, stressing the rarity of allergy as cause.