False positive diagnosis on (131)iodine whole-body scintigraphy of differentiated thyroid cancers.

(131)Iodine is used both to ablate any residual thyroid tissue or metastatic disease and to obtain whole-body diagnostic images after total thyroidectomy for differentiated thyroid cancer (DTC). Even though whole-body scan is highly accurate in showing thyroid residues as well as metastases of DTC, false positive results can be found, possibly leading to diagnostic errors and unnecessary treatments. This paper reviews the physiological and pathological processes involved as well as the strategy to recognize and rule out false positive radioiodine images.

Coexistence of multiple endocrine neoplasia type 1 and type 2 in a large Italian family.

To describe the coexistence of mutations of both the multiple endocrine neoplasia type 1 (MEN1) and type 2 (MEN2) genes in a large Italian family and evaluate if it could be associated with more aggressive clinical manifestations of the two syndromes. Blood samples were obtained for genetic and biochemical analyses. The RET gene exons (8, 10, 11, 13, 14, 15, 16, 18) and the MEN1 coding regions, including the exon-intron boundaries, were amplified by PCR and directly sequenced. We identified two germline mutations in the proband: the first one, K666M, located at the exon 11 of RET proto-oncogene and the second one, IVS4+1G>T, located in the MEN1 gene. The functional characterization of IVS4+1G>T variation, located in the splicing donor site of exon 4 of MEN1 gene, caused the in-frame junction of exon 3 to exon 5, thus obtaining a shorter protein. The same proband's germline mutations were found in 16 relatives out of 21 screened subjects: 8 carried IVS4+1G>T, 4 RET K666M, and 4 both the mutations. This is the second report in literature of coexistence in the same family of germline mutations of both RET proto-oncogene and MEN1 gene. The simultaneous presence of the two mutations was not apparently associated with more aggressive diseases, since at last follow-up all patients appeared to be disease-free or well compensated by medical therapy; finally, no one exhibited metastatic diseases.

Predictive value of recombinant human TSH stimulation and neck ultrasonography in differentiated thyroid cancer patients.

BACKGROUND: Serum thyroglobulin (Tg) stimulation by recombinant human TSH (rhTSH), in combination with neck ultrasonography (US), is an important tool in the first follow-up of differentiated epithelial cell thyroid carcinoma (DTC) patients. The objective of this study was to investigate if a second rhTSH stimulation, performed 2-3 years later, is of clinical utility in the follow-up of these patients. METHODS: One hundred and one consecutive ambulatory DTC patients were studied. The great majority of them (89/101) were low-risk patients, being stage I or II at tumor node metastasis (TNM) staging classification. All study patients had been treated by surgery and radioiodine ablation, and exhibited, at first rhTSH follow-up, either undetectable Tg (1-5 ng/mL) (rhTSH1-Tg+, n = 12 patients considered with uncertain prognosis), with no US evidence of residual disease. In all patients, serum Tg measurement after a second rhTSH stimulation and neck US were performed. RESULTS: At the second follow-up, all 89 rhTSH1-Tg-patients showed a negative US, and Tg became low positive only in one case, whereas it remained undetectable in the other patients. The overall negative predictive value of rhTSH1-Tg- was, then, 98.9%. Out of the remaining 12 patients (i.e., rhTSH1-Tg+ patients), 2 showed disease persistence/recurrence (with a positive predictive value of rhTSH1-Tg+ of 16.7%) and 6 became Tg-. CONCLUSIONS: A second rhTSH stimulation is useless in DTC patients who were rhTSH-Tg and imaging negative at first follow-up, while it is suggested in patients with detectable, although low, rhTSH-Tg levels at first follow-up: in the absence of clinical or US evidence of disease persistence, these patients should not be retreated by radioiodine, but simply scheduled for a later rhTSH stimulation.

Comparative evaluation of recombinant human thyrotropin-stimulated thyroglobulin levels, 131I whole-body scintigraphy, and neck ultrasonography in the follow-up of patients with papillary thyroid microcarcinoma who have not undergone radioiodine therapy.

CONTEXT: Although the prognosis of papillary thyroid microcarcinoma (PTMC) is usually excellent, the optimal follow-up strategy has never been investigated. OBJECTIVE: The objective of the study was to investigate the role of neck ultrasonography (US), whole-body scintigraphy (WBS), and serum thyroglobulin levels (Tg) after recombinant human (rh) TSH in the follow-up of very low-risk PTMC patients. DESIGN: The study was a 5-yr observational study based on a 6- to 12-month follow-up after near total thyroidectomy. SETTING: The study population consisted of ambulatory patients. PATIENTS: Eighty consecutive patients diagnosed with PTMC, who had not undergone postoperative radioiodine treatment because of unifocal tumor without lymph node metastases and who did not have anti-Tg antibodies, were included. MAIN OUTCOME MEASURES: WBS and Tg after both rhTSH and neck US were measured. RESULTS: rhTSH-Tg was 1 ng/ml or less in 45 (Tg-) and more than 1 in 35 (Tg+) patients. WBS showed no pathological uptake in any patient. US identified node metastases in two Tg (+) and one Tg (-) patients. rhTSH-Tg levels positively correlated with thyroid bed iodine uptake (r = 0.40, P < 0.0001). To date (32 +/- 13 months after surgery), all node-negative patients have undetectable Tg levels on LT(4) treatment and negative US. CONCLUSIONS: For the initial follow-up of PTMC patients without risk factors and anti-Tg antibodies and who did not undergo radioiodine treatment: 1) WBS is useless; 2) US is highly sensitive in detecting node metastases; and 3) detectable rhTSH-Tg levels mainly depend on small normal tissue remnants. In this subgroup of PTMC patients, neck US might be regarded as a primary tool for the initial follow-up.