technetium-tc-99m-medronate and Adenocarcinoma--Follicular

Detectability of bone metastases from differentiated thyroid carcinoma by technetium-99m hydroxymethylene diphosphonate ([99m]Tc-HMDP) bone scan is considered to be poor. Thallium-201 (201Tl) is also widely used for detecting metastatic lesions. Our present study was aimed at the evaluation of the combined use of (99m)Tc-HMDP and 201Tl imaging in successful detection of bone metastases from differentiated thyroid carcinoma. Twenty-seven thyroidectomized thyroid cancer patients (19 females, 8 males; 12 papillary type, 15 follicular type) with 77 bone lesions were included in this retrospective study. All of these patients received ablative doses of radioiodine. Thyroidal origin of the lesions was proved by positive iodine-131 (131I) uptake. In 131I-negative lesions, histological proof or absence of tumor markers other than thyroglobulin was considered when computed tomography (CT) and/or magnetic resonance imaging (MRI) suggested metastatic nature of the lesions. Of the 77 lesions, 58 (75.3%) were positive and 19 were negative in the (99m)Tc-HMDP bone scintigraphy, whereas 53 lesions (68.9%) could be detected by 201Tl scintigraphy. However, within the 19 (99m)Tc-HMDP-negative lesions, 14 showed abnormal accumulation of 201Tl, and within the 24 201Tl negative lesions, 19 were positive in (99m)Tc-HMDP scan. This resulted in a combined sensitivity of 93.5%. Our present study concludes that combined (99m)Tc-HMDP and 201Tl imaging is a sensitive and effective method for detecting bone metastases from thyroid carcinoma.

Topics: Adenocarcinoma, Follicular; Adult; Aged; Bone Neoplasms; Carcinoma, Papillary; Female; Humans; Iodine Radioisotopes; Male; Middle Aged; Radionuclide Imaging; Radiopharmaceuticals; Retrospective Studies; Sensitivity and Specificity; Technetium Tc 99m Medronate; Thallium Radioisotopes; Thyroid Neoplasms

Mixed medullary-follicular thyroid carcinoma (MMFTC) is a rare tumor with a metastatic behavior that has not been fully appreciated. Scintigraphy and radioiodine entrapment propensity of its metastases remains largely undescribed. The authors present a case of MMFTC with widespread bone and soft-tissue metastases, where every known site of metastases concentrated radioiodine intensely. The patient responded well to radioiodine therapy. The report suggests that the tumor may have a propensity to metastasize to the skeleton, and the metastases retain the ability to accumulate radioiodine.

Topics: Adenocarcinoma, Follicular; Bone Neoplasms; Carcinoma, Medullary; Female; Humans; Iodine Radioisotopes; Middle Aged; Radionuclide Imaging; Radiopharmaceuticals; Soft Tissue Neoplasms; Technetium Tc 99m Medronate; Thyroid Neoplasms

Iodine-131 is uniquely able to demonstrate iodine uptake of differentiated thyroid carcinoma (DTC), but precise localization may be difficult, especially in the thorax, due to the quality of image resolution with 131I and the lack of anatomical landmarks. When bone metastases do not show radioiodine uptake bone scintigraphy can be used to detect them. We studied two groups of patients. In group 1, 15 patients with known bone metastases of DTC were treated with 3.7 GBq 131I. After 4 or 5 days, technetium-99m hydroxymethylene diphosphonate (HMDP; 740 MBq) was injected and a whole-body scan with simultaneous acquisition of 131I and 99mTc-HMDP images was carried out using a large field of view gamma camera fitted with a high-energy collimator. Technetium uptake was abnormal in 47 of 63 localizations, being increased in 29 foci, decreased in 7 and heterogeneous in 11. The superimposition of 131I and 99mTc-HMDP scans permitted an accurate localization in 80% of spine metastases and in 46% of osseous thoracic localizations, even in the presence of lung metastases. In group 2, 9 patients, who had bone pain, neurological signs or elevated serum thyroglobulin, had DTC bone metastases without iodine uptake. They received a diagnostic dose of 99mTc-HMDP 3h prior to scintigraphy with a large field of view gamma camera fitted with a low-energy collimator. Technetium uptake was abnormal in 37 of 38 localizations, being increased in 34 foci and decreased in 3. One false-negative was found in a skull metastasis. In both groups of patients, 99mTc-HMDP scans were useful.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adenocarcinoma, Follicular; Adult; Aged; Bone Neoplasms; Carcinoma, Papillary; Female; Humans; Male; Middle Aged; Radionuclide Imaging; Technetium Tc 99m Medronate; Thyroid Neoplasms