Infantile hypertrophic pyloric stenosis in a 5-month-old baby: case report.

Hypertrophic pyloric stenosis is commonly seen in infants 2 to 4 weeks old. We report a case of pyloric stenosis diagnosed in a boy 5 months and 11 days old suffering from the sudden onset of vomiting. Gastric volvulus was initially diagnosed at another hospital. Abdominal ultrasonography at first using an Acuson 5-MHz transducer revealed a negative diagnosis. However, a tubular pyloric mass measuring 5.5 mm in thickness, 15 mm in the transverse diameter, and 2.0 cm in length was detected by a 7-MHz transducer immediately after the infant vomited. On physical examination, no abdominal mass was palpable. This suggested that this might have been a case of hypertrophic pyloric stenosis which was missed until the infant was older than 5 months. We believe this is the oldest reported case of infantile hypertrophic pyloric stenosis in Taiwan.