Uterus-like mass of the small intestine. Heterotopia or monodermal teratoma?

A 12-year-old girl with multiple lower-intestinal and urogenital tract anomalies and a past history of sacrococcygeal teratoma had an intramural mass of the ileum discovered as an incidental finding at surgery. The predominant mass had the features of the uterine fundus and two smaller contiguous nodules resembled the fallopian tube. A normal uterus and ovaries were observed at surgery. Somewhat similar lesions have been reported in the past in the ovary, ileum, scrotum, and possibly the bladder. Neither the metaplastic nor malformational theories are entirely satisfactory, yet they can be stated for most examples of heterotopias or choristomas.