Malignant carcinoid tumors in children.

The clinical, light microscopic, and ultrastructural features of four malignant carcinoid tumors in children, three boys and one girl ages 8--14 years, are described. Extensive metastases to multiple organs were present in three, and in the fourth child there was diffuse local infiltration of the bowel wall, which resembled a lymphoma. The primary tumor arose in the ileum in one child and in the transverse colon in another. In two children, the primary sites could not be determined; one patient is still alive and in the other, permission for autopsy was refused. Electron microscopy showed moderate numbers of neurosecretory granules in some cells in all cases. One patient with extensive metastases showed repeated partial response to radiotherapy and chemotherapy. Eight benign appendiceal carcinoids were seen at the same hospital over the same period, suggesting malignant carcinoids may be more common in children than often assumed.