Palpable contractile pyloric tumours in the newly born.

A palpable tumour which contracts and relaxes is generally accepted as conclusive confirmatory evidence of symptoms and signs suggestive of hypertrophic pyloric stenosis in infancy. The writer's experience, in common with that of other workers, is that a contractile tumour is present in 98% of infants with pyloric stenosis examined for the first time over the age of 2 weeks. A detailed study carried out over the past two and a half years suggests that the same significance cannot invariably be attached to the palpation of a contractile pyloric tumour in babies under 2 weeks of age. The purpose of this article is to describe the findings which have given rise to these doubts. The term 'tumour' is used throughout as meaning a clinically detectable swelling.