A female infant was born at a gestational age of 38 6/7 weeks and birthweight of 3076 g. The mother had Crohn’s disease but did not use any medication during pregnancy or in the year before pregnancy. Antenatal ultrasound at a gestational age of 20 weeks showed a poorly defined mass in the urogenital region connected with the right labium majus.

At birth, physical examination was unremarkable except for a perineal pedunculated solid mass of 3.0×2.0 cm, with partial skin involvement of the right labium majus (fig 1). Ultrasound showed a homogenous solid mass, with a small central cyst (0.5×0.5 cm), without infiltration in the skin or underlying muscles. Abdominal ultrasound showed no abnormalities.

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Figure 1

Congenital perineal hamartoma.

The perineal mass was surgically excised. Histopathology showed adipose tissue with fibrotic septa, small blood vessels and mature cartilage with central joining consistent with the diagnosis of congenital hamartoma.

Women with inflammatory bowel disease (IBD), including ulcerative colitis and Crohn’s disease, have an increased risk for preterm delivery and small for gestational age infants. In the case of ulcerative colitis one study suggested an increased risk of congenital malformations.1 The effect of disease activity and use of medication for IBD on adverse pregnancy outcomes has not yet been fully elucidated. Because congenital malformations have not been described in Crohn’s disease,2 our case probably reflects a coincidence. However, in the literature only one case report has described a congenital anorectal hamartoma,3 stressing the importance of reporting the coincidence of maternal Crohn’s disease and congenital hamartoma in the neonate.