[Immunohistochemical study of 17 cases of rectal neuroendocrine tumors].

Seventeen rectal neuroendocrine tumors ("Rectal Carcinoids") were studied by immunohistochemistry using antibodies directed against neuroendocrine markers: chromogranin A, neuron-specific enolase, synaptophysin, neuroendocrine peptides (ACTH, glicentin, glucagon, pancreatic polypeptide, somatostatin, vasoactive intestinal peptide) and antibody against serotonin. All patients with tumors measuring 1 cm or less had no specific symptoms and survived between fifteen months and eight years. Only one patient with a 6 cm poorly differentiated neuroendocrine carcinoma died less than one year after diagnosis. Only five out of seventeen tumors secreted serotonin. Most tumors were derived from L cell secreting glucagon, glicentin or pancreatic polypeptide.