Bone and liver images in medullary carcinoma of the thyroid gland: concise communication.

Thirty-four patients with surgically documented medullary carcinoma of the thyroid (MCT) and elevated serum calcitonin levels had Tc-99m phosphate bone and/or Tc-99m sulfur colloid liver images for suspected metastases. Liver images demonstrated metastatic lesions in nine of 32 patients (28%). Bone images were positive for metastases in eight of 30 patients (27%). Four of these eight abnormal bone studies detected only skeletal lesions, two demonstrated only extraosseous metastases, and two showed both kinds. Of 18 patients with both radionuclide bone studies and skeletal radiographs, four demonstrated skeletal metastases, and lesions were recognized on both examinations. This study demonstrates that radionuclide bone and liver images frequently detect metastatic lesions in patients with MCT and elevated serum calcitonin levels, and that some nonskeletal metastases in patients with this tumor display an unusual affinity for bone-seeking radiotracers.