sodium-pertechnetate-tc-99m and Adenocarcinoma--Papillary

Radioiodine and Tc-99 m pertechnetate scans are routinely relied upon to detect metastasis in papillary thyroid cancer; false-positive scans are relatively rare. To our knowledge, no published reports exist of sarcoidosis causing such selectively false-positive scans.. We present a case of a 41-year-old woman with known metastatic papillary thyroid cancer (T1bN1aMx) in whom sarcoidosis-affected cervical and mediastinal lymph nodes demonstrated uptake of thyroid-targeting radionuclides. Only the minority of these nodes demonstrated radionuclide uptake, raising the suspicion of adjacent or coexisting sarcoid and metastatic involvement. Selective uptake of thyroid-targeted radionuclides by isolated sarcoidosis is, to our knowledge, a previously undocumented occurrence.. Biopsies of uptake-negative mediastinal nodes revealed sarcoidosis. Pathology from a subsequent neck dissection excising uptake-positive cervical nodes also showed sarcoidosis, with no coinciding malignancy.. We document a case of sarcoidosis causing a selectively false-positive thyroid scintigraphy scan. It is useful for clinicians to be aware of potential false-positives and deceptive patterns on radionuclide scans when managing patients with both well-differentiated thyroid cancer and a co-existing disease affecting the nodal basins draining the thyroid gland.

Topics: Adenocarcinoma, Papillary; Adult; Biopsy, Fine-Needle; False Positive Reactions; Female; Humans; Iodine Radioisotopes; Lymph Nodes; Lymphatic Metastasis; Neoplasm Staging; Radionuclide Imaging; Sarcoidosis; Sodium Pertechnetate Tc 99m; Thyroid Neoplasms

The sodium/iodide symporter (NIS) has been recognized as an attractive target for radioiodine-mediated cancer gene therapy. In this study we investigated the role of human NIS for cellular uptake of the high LET alpha-emitter astatine-211 ((211)At) in comparison with radioiodine as a potential radionuclide for future applications. A mammalian NIS expression vector was constructed and used to generate six stable NIS-expressing cancer cell lines (three derived from thyroid carcinoma, two from colon carcinoma, one from glioblastoma). Compared with the respective control cell lines, steady state radionuclide uptake of NIS-expressing cell lines increased up to 350-fold for iodine-123 ((123)I), 340-fold for technetium-99m pertechnetate ((99m)TcO(4)(-)) and 60-fold for (211)At. Cellular (211)At accumulation was found to be dependent on extracellular Na(+) ions and displayed a similar sensitivity towards sodium perchlorate inhibition as radioiodide and (99m)TcO(4)(-) uptake. Heterologous competition with unlabelled NaI decreased NIS-mediated (211)At uptake to levels of NIS-negative control cells. Following uptake both radioiodide and (211)At were rapidly (apparent t(1/2) 3-15 min) released by the cells as determined by wash-out experiments. Data of scintigraphic tumour imaging in a xenograft nude mice model of transplanted NIS-modified thyroid cells indicated that radionuclide uptake in NIS-expressing tumours was up to 70 times ((123)I), 25 times ((99m)TcO(4)(-)) and 10 times ((211)At) higher than in control tumours or normal tissues except stomach (3-5 times) and thyroid gland (5-10 times). Thirty-four percent and 14% of the administered activity of (123)I and (211)At, respectively, was found in NIS tumours by region of interest analysis ( n=2). Compared with cell culture experiments, the effective half-life in vivo was greatly prolonged (6.5 h for (123)I, 5.2 h for (211)At) and preliminary dosimetric calculations indicate high tumour absorbed doses (3.5 Gy/MBq(tumour) for (131)I and 50.3 Gy/MBq(tumour) for (211)At). In conclusion, NIS-expressing tumour cell lines of different origin displayed specific radionuclide uptake in vitro and in vivo. We provide first direct evidence that the high-energy alpha-emitter (211)At is efficiently transported by NIS. Application of (211)At may direct higher radiation doses to experimental tumours than those calculated for (131)I. Thus, (211)At may represent a promising alternative radionuclide for future NIS-based tumour thera

Topics: Adenocarcinoma; Adenocarcinoma, Papillary; Animals; Astatine; Biomarkers, Tumor; Colonic Neoplasms; Gene Expression; Glioblastoma; Humans; Iodine Radioisotopes; Mice; Mice, Nude; Neoplasm Transplantation; Radionuclide Imaging; Radiopharmaceuticals; Reference Values; Reproducibility of Results; Sensitivity and Specificity; Sodium Pertechnetate Tc 99m; Symporters; Thyroid Neoplasms; Tissue Distribution; Tumor Cells, Cultured

A 27-year-old woman who presented with a left thyroid nodule was found to have hyperthyroidism caused by a syndrome of inappropriate secretion of TSH. The levels of free T3, free T4 and TSH were 9.50 pg/mL, 4.05 ng/dL and 2.16 microU/mL, respectively. Magnetic resonance imaging of the head revealed a pituitary macroadenoma. The TSH response to TRH stimulation was normal and responses of other anterior pituitary hormones to stimulation tests were also normally preserved. Administration of octreotide with iodine successfully reversed hyperthyroidism prior to total resection of pituitary adenoma, which was followed by hemithyroidectomy of the left thyroid five months later. Histologically, the resected pituitary adenoma was a TSH-producing adenoma (TSH-oma) and the thyroid nodule was a papillary adenocarcinoma. Serum TSH diminished to undetectable levels immediately following pituitary adenomectomy but gradually normalized over nine months. Coexistence of a TSH-oma with thyroid cancer is very rare and only two similar cases have previously been documented. This combination raises the possibility that TSH may be involved in tumorigenesis in the thyroid gland.

Topics: Adenocarcinoma, Papillary; Adenoma; Adult; Biopsy, Needle; Female; Humans; Hyperthyroidism; Iodine; Iodine Radioisotopes; Lymphatic Metastasis; Magnetic Resonance Imaging; Neoplasms, Multiple Primary; Octreotide; Pituitary Neoplasms; Sodium Pertechnetate Tc 99m; Thyroid Neoplasms; Thyroidectomy; Thyrotropin; Thyrotropin-Releasing Hormone; Ultrasonography

Sixteen patients with nonsuppressible solitary hot thyroid lesions (SHTL) identified on T3 suppression images using Tc-99m sodium pertechnetate were studied over a period of 5 years. Of the 16 patients, 7 (44%) had papillary adenocarcinoma (PAC) and 9 (56%) had follicular adenoma (FA). Of the 7 patients with PAC, 3 were toxic and 4 nontoxic. Of the 9 patients with FA, 2 were toxic and 7 nontoxic. The Tl-201 chloride thyroid scans were useful in locating SHTL and revealing extranodular thyroid tissue. The echography was sensitive to visualization of the nodule structures. However, there were no significant differences between the clinical findings, radionuclide images, and echograms between for PAC and FA. All patients with PAC were treated by partial thyroidectomy and there were neither regional nor distant metastasis in any of them. In conclusion, our study provided the following extremely interesting result: SHTL in the present series have a higher incidence of malignancy than previously reported autonomously functioning thyroid lesions (AFTL). Histological examination is necessary for the diagnosis and management of SHTL and surgical treatment should be considered.

Topics: Adenocarcinoma, Papillary; Adenoma; Adult; Aged; Female; Humans; Male; Middle Aged; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Thyroid Neoplasms