Falciform ligament abscess after resection of a patent urachus

Abscess formation of the falciform or round ligament of the liver is rare. A 15-year-old boy was diagnosed with Hirschsprung's disease after birth and underwent surgery for transverse colostomy at the site of the left upper abdomen in the neonatal period. A radical operation for Hirschsprung's disease was performed with a widely extended incision of the colostomy at 3 months of age. When he was 14 years old, he presented with lower abdominal pain due to a patent urachus. Six months after excision of the patent urachus, he returned to our outpatient clinic, showing pain and a palpable mass at the middle upper abdomen. We report herein a case of abscess formation of the round ligament of the liver after surgical resection of a patent urachus. We also review previous literature and discuss the possible pathogenesis and mechanisms of this phenomenon.