"Hot" carcinoma of the thyroid. Case reports and comments on the literature.

It seems somewhat difficult to exactly define the real number of case reports concerning the association of hyperfunctioning thyroid node and carcinoma; the overall incidence of this condition seems, however, to be very rare. Different inclusion criteria are probably a fairly relevant cause of variability in the number of cases reported during the years. A basic classification scheme, as the one here reported, may be of help in characterizing the different possible conditions: 1. the coexistence of carcinoma and focally hyperfunctioning tissue in the same gland but at different locations (not uncommon); 2. the presence of such a large tumour mass that it can compete with normal tissue for tracer uptake, despite being hormonogenetically uneffective in itself; 3. the carcinoma located in the hyperfunctioning adenoma; 4. the real hyperfunctioning carcinoma, where coincidence between hyperfunctioning tissue and malignancy is complete (very rare). Two cases are reported here, respectively belonging to the third and fourth of these categories (the most challenging from a diagnostic point of view). The matter is intrinsically poor from a statistical standpoint: it is therefore difficult to draw definitive conclusions on the subject in operative terms. It is however felt that the systematic evaluation of oncological risk in thyroid nodes, occasionally recommended in the literature, may be cumbersome and not necessarily cost-effective.

How gender and age affect iodine-131-OIH and technetium-99m-MAG3 clearance.

OBJECTIVE: The relationship between age and effective renal plasma flow (ERPF) results, as measured in nuclear medicine, is well known. This paper explores the relationships among gender, age, and ERPF measurements. After reading this paper, the nuclear medicine technologist should be able to: (a) discuss the importance of establishing normal range values for ERPF that include age and gender variables; (b) state how age affects ERPF results; and (c) state how gender affects ERPF results.

Thyroid nodules and Doppler ultrasonography. A new element for an old puzzle?

BACKGROUND: Whether Doppler ultrasonography (DU) may be of help in characterizing thyroid nodes is still under debate: both good and unsatisfactory results have been claimed, either in evaluating the presence of malignancy or in identifying hyperfunctional structures. METHODS: In this paper, the scintigraphic and Doppler patterns of 80 thyroid nodes have been compared, in the hypothesis that there may be some correlation between functional status and vascularity of the node; a small group of cyto-histological information were considered too. RESULTS: Perilesional flux seems to be, in general, somewhat more frequent than intranodal or mixed patterns: this is, however, true for all the groups of nodular functional conditions studied (peripheric flux was found in 70.2% of hyperfunctioning, 63.6% of isofunctioning and 59.3% of hypofunctioning nodes; intranodular flow was present in 18.9, 9 and 21.8% of hyper-, iso and hypofunctioning nodes respectively; mixed flow was found in 10.8% hyper, 27.2% iso and 18.7% hypofunctioning nodes). CONCLUSIONS: A prevalence of peripheric flow pattern is almost evenly distributed in all class of differently functioning nodes. Our data support the conclusion that no reliable correlations exist between scintigraphic and DU patterns: DU may not, therefore, be considered a valid substitute for nuclear imaging.

Appearance of Graves'-like disease following regression of autonomously functioning thyroid nodules. Two case reports.

Two cases are reported in which a rare hyperthyroidism appeared: in a female after radioiodine therapy for toxic multinodular goiter and in a male after spontaneous regression of a toxic adenoma. Both subjects showed a relapse of hyperthyroidism after a period of well-being lasting almost eight months in the first and three years in the second. Thyroid scans were consistent with an immunogenic hyper-thyroidism because there was a diffuse trapping of 131I in the thyroids while the previous autonomously functioning nodules became "cold". Serum TSH was undetectable, free thyroid hormones were increased, TgAb and TRAb were always normal in both patients, TPO became moderately positive only in the female. TRAb were evaluated only by radioimmunoassay. In these patients a diagnosis of Graves'-like disease was made because of the clinical and scintigraphic pattern. Moreover US did not reveal nodular areas different from those highlighted by scans. None of the subjects developed ophthalmopathy and/or dermopathy. Our remarks show that in particular subjects, genetically susceptible to autoimmunity, the release of antigenic materials secondary to destruction of thyroid nodules can trigger an autoimmune thyroid response resembling Graves' disease. Therefore all patients carrying autonomous nodules should be carefully evaluated for a possible autoimmune disposition before treatment and after admission. Radionuclide imaging is a simple, reliable, non invasive technique which can be applied in the evaluation of the etiology of the relapses.

Female "varicocele": two cases diagnosed by labeled red blood cell angioscintigraphy and treated by percutaneous phlebography and embolization.

Varicocele, a varicosity of the gonadal venous plexus, is a well-recognized disorder occurring in up to 10% of men. In women, an analogous varicosity of the salpingo-ovarian plexus is rare. This may be explained, in part, by the lack of obvious findings on clinical examination in women compared with men and the need, until recently, to use invasive venographic methods to confirm the diagnosis. Two cases of "female varicocele" diagnosed by means of echo Doppler and Tc-99m red blood cell scintigraphy and their cure by percutaneous phlebographic occlusion of the ovarian venous varicosity are described.

Renal SPECT with Tc-99m DMSA in children with upper urinary tract infections using a triple-headed gamma camera.

UNLABELLED: Renal cortical scintigraphy with Tc-99m DMSA provides an excellent imaging modality for the assessment of cortical damage secondary to upper urinary tract infection (UTI). METHODS: The authors evaluated 48 children with UTI, 12 of whom had a history of vescico-ureteral reflux (from first of fourth degree), by planar scintigraphy and SPECT using a triple-headed gamma camera equipped with parallel-hole, high-resolution collimators. RESULTS: SPECT images yielded positive findings in 36 kidneys, whereas planar scans yielded positive findings in 18 kidneys. The total number of lesions detected by SPECT was 51, whereas the number found with the planar technique was 23. CONCLUSION: This study demonstrates the superiority of SPECT scanning in detecting kidney lesions in children with UTI.

Feasibility of simultaneous Tc99m sestamibi and 2D-echo cardiac imaging during dobutamine pharmacologic stress. Preliminary results in a female population.

Feasibility of simultaneous 2D-Echo and SPECT Tc99m Sestamibi imaging during dobutamine infusion was evaluated in a female population with suspected coronary artery disease and scheduled for diagnostic coronary angiography. A total of 49 consecutive subjects were studied. Patients under continuous ECG and 2D-Echo monitoring underwent standard dobutamine infusion at increasing doses to a diagnostic end-point. Tc99m Sestamibi was administered at the peak of the dobutamine effect. With this approach, 35 patients were identified correctly by 2D-Echo (Sensitivity = 60.1%; Specificity = 83.3%; Agreement = 71.4%; k = 0.43). Perfusion imaging with Tc99m Sestamibi resulted in correctly identifying 41 patients (Sensitivity = 83%; Specificity = 84%; Agreement = 83.6%; k = 0.67). Combining information obtained from the two tests resulted in increased specificity (92%) and decreased sensitivity (64%). Simultaneous assessment of perfusion and function with Tc99m Sestamibi and 2D-Echo imaging during dobutamine administration is easily performed without added risk or discomfort to the patient. Tc99m Sestamibi appeared to be slightly superior to 2D-Echo for the detection of CAD in this population, but the difference does not reach conventional statistical significance. The combined use of the two independent tests did not substantially improve the diagnostic accuracy of each method.

An unusual adrenal metastasis secondary to Hürthle cell carcinoma of the thyroid.

A 66-year-old woman with Hürthle cell thyroid carcinoma associated with a right adrenal gland metastasis suspected on a postradioiodine therapy scan, is reported. Histology specimens confirmed the suspicion. Adrenal metastases have never been reported previously in this kind of tumor. On radionuclide imaging, there was marked I-131 uptake in the tumor remnant and its metastases, and the tumor spread through both lymphatic and hematogenous routes, as shown by lymph node, bone, and lung metastases.

A brain metastasis, with no uptake of 99mTc-ECD, secondary to Hurtle cell carcinoma of the thyroid.

Visualization of cerebral perfusion with Single Photon Emission Computed Tomography (SPET) needs lipophil radiotracers which are able to cross the intact blood-brain-barrier (BBB); moreover local uptake must reflect regional cerebral blood flow. In the last decade many radiopharmaceuticals have been suggested and employed for this purpose. Recently a new molecule has been synthesized: technetium-99m-labeled ethyl cysteinate dimer (99mTc-ECD). Commonly, SPET of the brain with perfusion tracers is performed to identify ischemic regions. We describe a patient with a bulky cerebral metastasis, secondary to Hurthle cell carcinoma of the thyroid, which concentrated radioiodine. Brain metastases secondary to differentiated carcinoma of the thyroid are very rare and when treated with 131-I may provoke serious neurological problems. Therefore we decided to perform a brain SPET with 99mTc-ECD to exclude regional perfusion defects and deafferentation phenomena. Brain CT showed only the large metastasis. SPET images, reconstructed according to standard tomographic planes of the head: transverse, coronal and sagittal revealed no uptake of 99mTc-ECD within the metastasis and no regional perfusion defects related to compression phenomena or deafferentation. 99mTc-ECD has never been used to image cerebral neoplasm of whatever origin.

A case of bronchial carcinoid: diagnosis and follow-up with 111In-DTPA-octreotide.

Scintigraphy with radiolabelled analogue of somatostatin is highly sensitive in detecting carcinoid tumors especially if performed with Single Photon Computed Tomography (SPECT). In this report we describe our experience with 111In-DTPA-Octreotide in a female patient affected by a small asymptomatic intrabronchial carcinoid demonstrated by CT scan and bronchial endoscopy performed after recurrent left pneumonias. Planar views and SPECT images, using 111In-DTPA-Octreotide, were collected before and four hours after the first endoscopic laser resection. All groups of SPECT images were positive in the left parahilar region but at a different degree. Scans performed after resection showed a low degree of uptake which was considered to be probably secondary to local swelling; CT scan was negative. Follow up endoscopic biopsy repeated at six months, showed a relapse always in the same site; CT scan of the thorax was again negative. 111In-DTPA-Octreotide images obtained at twelve months were positive always in the left parahilar region, CT scan was negative but another biopsy was not possible. Therefore it was suspected a relapse of the carcinoid which was probably growing only through the bronchial wall without spreading towards the bronchial lumen and/or the lung parenchima. In this occasion, it was also thought that images collected four hours after resection could be positive not only for swelling but for a relapse as well. In every scintigraphic session, SPECT images presented higher quality than planar. This case suggests that 111In-DTPA-Octreotide SPECT is a non-invasive diagnostic technique which could be applied as a follow-up tool especially to patients with no-secreting carcinoid neoplasm and/or with negative or doubtful endoscopic and radiological investigations.

131I MIBG/111In octreotide mismatch in a patient with liver metastases secondary to a carcinoid of unknown origin.

Carcinoids, tumors arising from enterochromaffin cells, represent the most common type of gastrointestinal endocrine neoplasm; they are often multiple and may appear anywhere in the gut. Carcinoid tumors may also occur in bronchi and ovaries. Classic symptomatology includes secretory diarrhea, flushing, edema, bronchospasm and cutaneous teleangectasias; however, over 30% of patients with demonstrably elevated serotonin levels may not exhibit any symptoms at all. The diagnosis of carcinoid tumor is typically made by measurement of 24-hour urinary excretion of 5-hydroxyindoloacetic acid. Commonly, tumor localisation is established with CT, US, NMR and arteriography. MIBG scintigraphy is also used to visualize tumors deriving from neuroendocrine cells as carcinoid. These tumors may express somatostatin receptors located on the cell surface. Therefore 111In Octreotide (Octreoscan), a somatostatin analogue, can be employed for tumor localisation. A 32-years-old man with liver metastases secondary to a carcinoid tumor of unknown origin is presented. Classic carcinoid symptoms were absent. Diagnosis was supported by elevated values of urinary 5-hydroxyindolocetic acid and liver fine-needle aspiration. Abdominal US and CT scan detected only liver masses but not the primary tumor. Arteriography was not performed. 131I MIBG and 111I octreotide scans both failed in locating the primary cancer too; only the second tracer showed marked uptake in liver metastases. Beside localization, these two tracers give also informations about the following therapy especially in malignant tumors where local resection isn't an adequate treatment.

An unusual false-positive scan in a patient with pericardial effusion.

Uptake of I-131 in the pericardial area is described in an asymptomatic patient who underwent total body scan for recurrent papillary thyroid cancer. Ultrasonography demonstrated a small pericardial effusion that persisted after I-thyroxine therapy was reinstituted. Two I-131 therapeutic doses were given, and follow-up total body scans were performed during the next 6 years. Although tracer accumulation in the neck was eliminated and the serum thyroglobulin level was not elevated, I-131 uptake persisted in pericardial effusion. Despite diligent study, no neoplastic, infectious, or autoimmune etiology could be demonstrated, and we thus classified it as idiopathic pericardial effusion. This phenomenon should be considered when interpreting I-131 scans that show I-131 uptake in the region of the heart.

Concurrent Plummer's disease and parathyroid adenoma. Diagnostic and therapeutic approaches to a difficult clinical problem.

When mild asymptomatic hypercalcemia occurs in a patient with hyperthyroidism, it may or may not be due to concurrent hyperparathyroidism and at times only the control of the hyperthyroidism will resolve the problem. Moreover, the presence of hyperfunctioning thyroid nodules will interfere with Tl-201/Tc-99m pertechnetate parathyroid scintigraphy. Initial treatment of hyperthyroidism with I-131 in this situation controls hyperthyroidism and permits successful localization of parathyroid adenomas, which may then be excised--a result that was achieved in three cases.

Localization of parathyroid enlargement: experience with technetium-99m methoxyisobutylisonitrile and thallium-201 scintigraphy, ultrasonography and computed tomography.

Technetium-99m methoxyisobutylisonitrile (MIBI), like thallium-201, has recently been introduced as a myocardial perfusion agent and is now also showing very promising results in parathyroid scintigraphy. The results of 201Tl/99mTc-pertechnetate and 99mTc-MIBI/99mTc-pertechnetate subtraction scintigraphy, ultrasonography and computed tomography are presented in a series of 43 patients operated on for hyperparathyroidism. All four imaging modalities were confirmed to be reliable, scintigraphy being the most accurate. Sensitivities ranged from 81% to 95%, that of 99mTc-MIBI being the highest. Moreover this tracer, which has more favourable physical and also biochemical properties, yielded images of superior quality. This allowed localization of the lesion by visual inspection only in as many as 86% of the patients with positive 99mTc-MIBI/99MTc-pertechnetate subtraction scintigraphy. We believe that the higher sensitivity, superior image quality and lower cost of 99mTc-MIBI imaging will make 99mTc-MIBI the new radiopharmaceutical of choice for parathyroid scintigraphy (when one take into account the stability of labelling with large activities it is possible to perform three or four cardiac studies together with one parathyroid scintigraphic examination using one lyophilized vial).

L-thyroxine malabsorption due to the injection of herbal remedies.

Two patients are described in whom the absorption of l-thyroxine was impaired by non-prescription herbal and nutritional remedies. The absorption of thyroid hormones is discussed and an approach to the problem of patients who appear to be unresponsive to the usual doses of thyroid hormones is suggested.