Osteolytic and osteoblastic metastases due to carcinoid tumors.

Gastrointestinal carcinoid tumors arising from the foregut and hindgut may metastasize within the abdomen. Bone metastases are rare, but their occurrence is well established. Both osteoblastic and osteolytic metastases can occur in the same patient without any bone symptoms. Three patients with malignant carcinoid tumors had no bone symptoms but demonstrated extensive bone metastases on radionuclide bone scans. Some of these lesions were abnormal on corresponding roentgenograms and some areas were negative on roentgenograms. The use of radionuclide bone scanning in the evaluation of patients with malignant carcinoid tumor is emphasized.