Leiomyosarcoma of the transverse colon in a neonate: a rare cause of meconium peritonitis.

A rare case of a newborn infant with leiomyosarcoma of the transverse colon is reported. The condition was associated with meconium peritonitis due to a perforation proximal to a portion of the transverse colon that was completely surrounded by the tumor. The 12 previously published cases of leiomyosarcoma of the colorectum in childhood are reviewed, and the pathogenesis of meconium peritonitis is discussed.