Tc-99m MIBI SPECT in detecting metastatic papillary thyroid carcinoma in patients with elevated human serum thyroglobulin levels but negative I-131 whole body scan

Papillary carcinomas are the most common thyroid malignancies. They invade the regional lymphatics and metastasize frequently to local lymph nodes in the neck. Distant metastasis, generally to the lungs, is also common. The aim of this study is to evaluate the effectiveness of single photon emission computed tomography (SPECT) with technetium-99m methoxyisobutylisonitrile (Tc-99m MIBI) in detecting metastatic lesions in patients with papillary thyroid carcinoma (PTC) after nearly total thyroidectomy and radioiodine (I-131) treatment who present with elevated serum human thyroglobulin (hTg) levels but negative I-131 whole body scan (WBS). METHODS: Twenty patients of PTC who underwent nearly total thyroidectomy and I-131 treatments were included in this study. All of the 20 patients had negative I-131 WBS results and elevated hTg levels (hTg > or = 20 microIU/mL) under thyroid-stimulating hormone (TSH) stimulation (TSH > or = 30 microIU/mL). Technetium-99m MIBI SPECT was performed to detect metastatic lesions. RESULTS: Technetium-99m MIBI SPECT demonstrated lesions in 10 patients. Technetium-99m MIBI SPECT failed to demonstrate lesions in nine patients including small lymph node and lung metastases. CONCLUSIONS: This study showed that Tc-99m MIBI SPECT is a useful tool to detect metastatic lesions in PTC with elevated hTg but negative I-131 WBS. However, small lymph node and lung metastases may be missed in Tc-99m MIBI SPECT. In the latter circumstance, other imaging studies should be included in the follow-up protocol.     

Follow-up of thyroid cancer patients with "poor prognosis".

High-risk differentiated thyroid carcinoma is the most frequent thyroid tumor of "poor prognosis": this mainly includes patients with extra-thyroidal invasion, or distant metastases, younger patients (<16 years old), and older patients (>45 years old). Among them, metastatic patients with multiple organ involvement at the time of initial diagnosis have the higher risk of cancer death. Additionally, certain histological subtypes are classically more aggressive, and bilateral cervical lymph-nodes metastases or mediastinal involvement may also impart a poorer overall prognosis. More aggressive therapy to produce undetectable thyrotropin levels is usually recommended, although the benefit of such therapy and how long to maintain thyrotropin suppression has not been definitively established. As about two-thirds of the recurrences occur within the first decade after initial treatment, this first decade seems particularly critical, even if follow-up is necessary throughout the patient's life as recurrences may also occur over several decades. Coupled thyroglobulin (Tg) and Tg antibody (TgAb) assay is the first-line tool in their follow-up. Tg measurement obtained either after LThyroxine withdrawal or rhTSH stimulation may permit the selection of patients for scanning with a high dose of 131-I. When either basal Tg level is high or TgAb increases, it appears preferable to schedule patients directly for 131-I therapy followed by a post-therapy WBS. Therefore, the discovery of foci of 131-I uptake is possible in 60 to 80% of such patients. 131-I therapy is proposed as long as metastases trap 131-I without any limit to the cumulative dose of 131-I, although the risk of leukemia rises slightly above a 500 mCi (18,500 MBq) cumulative dose. But when 131-I post therapeutic WBS is negative, any further administration of 131-I is not justified. Alternative imaging procedure is thus required to detect metastases that have lost their capacity to concentrate 131-I. Conventional imaging with ultrasonography of the neck, a CT scan or an MRI of the neck and the chest and bone imaging, and even non-conventional imaging with other isotope procedures, such as 18-FDG whole-body scanning, are nowadays indicated. The goal is to localize those metastases in order to propose the more adequate therapeutic options.     

Lobectomy versus total thyroidectomy in children with post-Chernobyl thyroid cancer: a 15 year follow-up

In 1994, 21 Belarus children presenting papillary thyroid cancer (PTC) diagnosed after the Chernobyl disaster, and already submitted to subtotal surgery, underwent thyroid re-operation and post-operative radioiodine (131(I)) therapy. All were re-evaluated after a 15-year follow-up, to evaluate the results of partial versus total thyroidectomy. Nineteen out of 21 children (mean age 9.2?years) had previously undergone a lobectomy. All cases underwent re-operation in 1994. Histology revealed a PTC in the residual lobe in three cases, three had lymph node metastases. After surgery, 20 patients underwent 131(I) therapy. The post-131(I) whole body scan was negative in seven cases, showed neck node metastases in five, lung metastases in three, multiple associated metastases in six. The follow-up was performed with rhTSH-stimulated serum thyroglobulin (Tg) evaluation and ultrasonography. Twenty patients showed Tg <1?ng/ml and negative ultrasonography; the patient who refused 131(I) therapy showed a thyroid remnant and a Tg of 32?ng/ml. Chi-square analysis showed significantly higher prevalences of residual cancer in the neck or lung, lymph node metastases, and re-operations (before completion) in patients who had undergone lobectomy than in those who had undergone completion thyroidectomy and 131(I) therapy. The surgical complications after lobectomy were similar to those after completion thyroidectomy. A less-than-total thyroidectomy should not be indicated in patients with radiation-induced PTC, due to the high risk of residual cancer in the thyroid left in situ. The results of this study favor total thyroidectomy as the initial treatment for thyroid cancer in children exposed to fallout radiation.     

Relationship of sodium/iodide symporter expression with I131 whole body scan uptake between primary and metastatic lymph node papillary thyroid carcinomas

The aim of the present study was to evaluate total and membranous Na+/I- symporter (NIS) expressions in papillary thyroid carcinoma (PTC) tissue, correlation of NIS expression between primary and metastatic lymph node (LN) PTC tissues, and relationship of NIS expression with I131 whole body scan (WBS) uptake between primary and metastatic LN PTC tissues by analyzing 17 pairs of primary and metastatic LN PTC tissues. Staining positivity was calculated, and staining intensity was graded as negative (0), weak (1+), moderate (2+) and strong (3+). In primary PTC tissues, positivities and intensities of normal cells were higher than those of carcinoma cells but had no correlation with those in matched metastatic LN PTC tissues. In classic type, positivities, intensities and membranous intensities (mIS) were correlated between primary and matched metastatic LN PTC tissues. In patients aged younger than 45 yr, positivities and intensities in primary PTC tissues had correlation with those in matched metastatic LN PTC tissues. Positivities, intensities, mIS and pathological subtype of carcinoma cells in primary PTC tissues were not correlated with age, tumor size, TNM stage, MACIS score and thyroglobulin (Tg) levels at the time of I131 WBS. Sensitivity, specificity, as well as positive and negative predicted values of mIS in patients with I131 WBS uptake were 69.2, 75, 90 and 42.9% in primary PTC tissues, and 92.3, 100, 100 and 80% in metastatic LN PTC tissues. The results of mIS taken either as positive or negative were correlated with those of I131 WBS after controlling for age. Our results demonstrate that PTC tissues have altered total and membranous NIS expressions, suggesting that NIS expression in primary PTC tissues may predict NIS expression and I131 WBS uptake in matched metastatic LN PTC tissues.     

I-131 therapy for thyroglobulin positive patients without anatomical evidence of persistent disease

OBJECTIVE: the aim of this retrospective study was to evaluate the diagnostic relevance of I-131 whole body scan (WBS) performed after second empirical therapeutic doses of iodine-131 (I-131) in thyroglobulin (Tg)-positive thyroid cancer patients without evidence of local and distant metastasis. We also evaluated the efficacy of second empirical therapeutic doses of I-131 in these patients. METHODS: we retrospectively compared the results of diagnostic I-131 WBS and post-therapy scans of second therapeutic doses of I-131 in 38 patients with detectable Tg while off T4 therapy (TSH>25 mlU/ml). All patients underwent a near-total or total thyroidectomy and I-131 ablation with 75-125 mCi. All of the reported subjects had no prior evidence for detectable disease before second high dose empirical I-131 therapy. RESULTS: there was almost complete concordance in uptake between diagnostic I-131 WBS and final scans carried out after second I-131 therapy in 22 out of 38 patients. Whereas abnormal foci of new uptake was detected in all of the remaining 16 patients, seven of them were found to have negative diagnostic WBS results. Distant metastases were observed in 3 of 16 subjects and mediastinal uptake was found in 2 of 16 patients in post-therapy scan. During the subsequent follow-up, extending from 8-46 months, 6 out of 16 patients showed normalization of serum Tg levels while off T4. Serum Tg levels were normalized in 3 out of 7 patients who had negative WBS results, increased in one and unchanged in the remaining 3. None of the patients with distant metastases had normalization of Tg levels. Totally, 6 out of 38 showed normalization of Tg levels while off T4 therapy. CONCLUSION: the empirical therapeutic doses of 1-131 may help in localization of the disease in Tg positive patients without anatomical evidence of persistent disease, but the effect of I-131 therapy on long-term survival is not obvious.     

F18-fluorodeoxyglucose positron emission tomography in detecting metastatic papillary thyroid carcinoma with elevated human serum thyroglobulin levels but negative I-131 whole body scan

Papillary carcinomas are the most common thyroid malignancies. They invade the regional lymphatics and metastasize frequently to local lymph nodes in the neck. Distant metastasis, generally to the lungs, is also common. METHODS: The aim of this study is to evaluate the effectiveness of F18-fluorodeoxyglucose (FDG) positron emission tomography (PET) to detect metastatic lesions in patients with papillary thyroid carcinomas (PTC) after nearly total thyroidectomy and I-131 treatments who present with elevated human serum thyroglobulin (hTg) levels but negative 1-131 whole body scan (WBS). Twenty patients with PTC who underwent nearly total thyroidectomy and radioiodine treatments were included in this study. RESULTS: All of the 20 patients had negative I-131 WBS results and elevated hTg levels (hTg > or = 2.0 microIU/mL) under thyroid-stimulating hormone (TSH) stimulation (TSH > or = 30 microIU/mL). CONCLUSIONS: FDG-PET was perform to detect metastatic lesions. F18-fluorodeoxyglucose-PET could detect hypermetabolic lesions in 17 patients but failed to demonstrate miliary pulmonary metastases in two patients. No definite lesion was found in FDG-PET, x-ray chest computed tomography (CT) and other imaging studies of the remaining one patient This study showed that FDG-PET is a useful tool in detecting metastatic lesions in PTC with elevated hTg but negative I-131 WBS. However, miliary lung metastases may be missed in FDG-PET. In this circumstance, chest CT should be included in the follow-up protocol.     

Outcome in patients with differentiated thyroid cancer with negative diagnostic whole-body scanning and detectable stimulated thyroglobulin

BACKGROUND: Management of patients with differentiated thyroid carcinoma with negative diagnostic radioiodide scanning and increased serum thyroglobulin (Tg) concentrations is a widely debated problem. High-dose iodine-131 treatment of patients who have a negative (131)I diagnostic whole-body scan (WBS) is advocated. However, the therapeutic benefit of this "blind" treatment is not clear. OBJECTIVE: To investigate the course of serum Tg during thyroid hormone suppression therapy (Tg-on) and clinical outcome in patients with negative diagnostic (131)I scanning and increased serum Tg concentrations during thyroid hormone withdrawal (Tg-off), after treatment with high-dose (131)I. DESIGN: Retrospective single-center study. METHODS: Fifty-six patients were treated with a blind therapeutic dose of 150 mCi (131)I. Median follow-up from this treatment until the end of observation was 4.2 Years (range 0.5-13.5 Years). RESULTS: The post-treatment WBS revealed (131)I uptake in 28 patients, but none in the remaining 28 patients. In this study the Tg-on values did not change after treatment in either the positive or the negative post-treatment WBS group. During follow-up, 18 of the 28 patients with a positive post-treatment WBS achieved complete remission, compared with 10 of the 28 patients with a negative post-treatment WBS. Nine patients in the negative group died, but no patients died in the positive post-treatment group (P=0.001). CONCLUSIONS: High-dose iodine treatment in diagnostically negative patients who have a negative post-treatment scan seems to confer no additional value for tumor reduction and survival. In patients with a positive post-treatment scan, high-dose iodine treatment can be used as a diagnostic tool to identify tumor location, and a therapeutic effect may be present in individual cases.     

Radioiodine treatment with 30 mCi after recombinant human thyrotropin stimulation in thyroid cancer: effectiveness for postsurgical remnants ablation and possible role of iodine content in L-thyroxine in the outcome of ablation

The main steps in the management of differentiated thyroid cancer are thyroidectomy, treatment with iodine-131 ((131)I), and follow-up with whole-body scanning (WBS) and serum thyroglobulin (Tg) determination. Both (131)I treatment and follow-up require maximum stimulation of normal or pathological thyroid remnants by TSH. The use of recombinant human TSH (rhTSH) has been shown to be useful for follow-up, whereas previous reports are not univocal regarding the use of (131)I postsurgical ablation of thyroid remnants, at least when low doses (30 mCi) of (131)I are administered. A possible explanation for the diminished effectiveness of (131)I treatment after rhTSH may be the interference of iodine content of L-thyroxine (L-T4) therapy during the protocol of administration of rhTSH. We have evaluated the effectiveness of stimulation by rhTSH for radioiodine ablation of postsurgical remnants, stopping L-T4 the day before the first injection of rhTSH and restarting L-T4 the day after (131)I. The study included two groups of patients: group 1 included 16 patients with differentiated thyroid cancer (15 papillary cancers and 1 follicular cancer, stages I and II), who were treated with 30 mCi (131)I with the aid of rhTSH, using the standard protocol but stopping L-T4 as stated previously; and group 2 included 24 patients with the same features (histology and stage) of disease treated with 30 mCi in the hypothyroid state after L-T4 withdrawal. In both groups, serum TSH reached a very good stimulation level [76-210 U/liter (mean, 112 +/- 11 SE) and 38-82 U/liter (mean, 51 +/- 3 SE), respectively]. At the first WBS (after (131)I treatment), all patients showed thyroid remnants. Furthermore, two patients of the first group and three patients of the second group showed lymph node metastases. After 1 yr, all patients were studied again and underwent WBS with a tracer dose of (131)I and serum Tg measurement using rhTSH with the same protocol in both groups. The percentage of ablation (undetectable Tg and a negative WBS) was higher, although not reaching statistical significance, in patients treated with rhTSH: 81.2% in patients treated by rhTSH withdrawal and 75.0% in patients treated by L-T4 withdrawal, respectively. No patient experienced symptoms of hypothyroidism during the 4 d of L-T4 interruption, and serum T4 remained in the normal range. Urinary iodine was analyzed in both groups and compared with a control group of patients who received, for diagnostic purposes, rhTSH without stopping L-T4. In the first group, urinary iodine was 47.2 +/- 4.0 microg/liter (mean +/- SE; P = 0.21 vs. the second group, P = 0.019 vs. control group). In the second group, urinary iodine was 38.6 +/- 4.0 microg/liter (mean +/- SE; P < 0.001 vs. control group); urinary iodine in the control group was 76.4 +/- 9.3 microg/liter (mean +/- SE). Our data show that rhTSH, as administered in the protocol stated previously, allows at least the same rate of ablation of thyroid remnants when low doses (30 mCi) of (131)I are used. The possible role of interference of iodine content in L-T4 is not surprising if we consider that the amount of iodine in 30 mCi is negligible (5 microg) compared with the amount of iodine content in a daily dose of T(4) ( approximately 50 microg). The cost of rhTSH seems modest compared with the high cost of complex therapeutic regimens in other areas of oncology and in consideration of the well-being of patients and of the high level of effectiveness of the treatment.     

The use of recombinant human TSH in the follow-up of differentiated thyroid cancer: experience from a large patient cohort in a single centre

BACKGROUND: Periodic evaluation of serum thyroglobulin (Tg) and whole body 131I imaging (131I-WBS) are essential in the follow-up of differentiated thyroid carcinoma (DTC); both diagnostic modalities require stimulation by high levels of TSH. Administration of recombinant human TSH (rhTSH) is an alternative to the withdrawal of thyroid hormone therapy. OBJECTIVE: The aim of this study was to report our experience in the use of rhTSH for the management of patients with DTC. PATIENTS: One hundred and four patients were enrolled in the study. A dose of 10 U of rhTSH therapy was injected intramuscularly for 2 consecutive days; 24 h after the second dose of rhTSH the patients were administered 4--5 mCi of 131I and, 48 h later, WBS was performed. RESULTS: In all patients, baseline mean serum Tg and TSH levels were 2.4 +/- 1.9 ng/ml and 0.0153 +/- 0.0232 mIU/l, respectively. Basal Tg levels were detectable in 58 out of 104 patients. After rhTSH injection, mean serum TSH levels rose to 122.67 +/- 47.36 mIU/l. Stimulated serum Tg levels increased to greater-than-or-equal 5 ng/ml and the 131I-WBS showed an uptake in 18 patients (17.4%). Among them there were three with bone metastases and one with brain metastases, who reported violent skeletal pain and a severe headache, respectively. These were caused by the growth of tumour mass of metastases induced by rhTSH administration. CONCLUSIONS: The use of rhTSH avoids the debilitating effects of hypothyroidism and its use successfully promotes iodine uptake and increases the sensitivity of serum Tg testing. The risk of causing serious side-effects recommends performing skull magnetic resonance and radionuclide bone scan in cases of suspected brain or skeletal metastases.     

Intrathyroideal papillary thyroid carcinoma presenting with a solitary brain metastasis

Papillary thyroid carcinoma (PTC) is the most common type of well-differentiated thyroid carcinoma and typically has an excellent prognosis. The incidence of distant metastasis from PTC is low. However, once metastasis has developed in a distant site, prognosis is markedly diminished. Brain metastases from PTC are extremely rare. No consensus regarding management has yet been reached. We report on the case of a patient who presented with signs of intracranial hypertension. Cranial magnetic resonance imaging (MRI) identified a lesion of the right temporofrontoparietal lobe. The patient underwent a craniotomy with a total removal of the tumor. Histologic examination of the lesion showed a metastasis of papillary adenocarcinoma. We observed a cold nodule in the right lobe of the thyroid on physical examination and imaging techniques (e.g., CT and scintigraphy). Fine-needle-aspiration cytology of the nodule was reported as PTC. A total thyroidectomy was performed and histopathological examination showed intrathyroidal variant of PTC. Postoperatively adjuvant whole brain radiation therapy with 44 Gy to multiple brain metastases of PTC was applied. One month later, the patient then underwent ¹³¹I radioiodine therapy with 150 mCi of ¹³¹I given orally. In conclusion, the present case underwent an aggressive multimodal approach therapy. This report indicates that the early detection and control of brain metastases may contribute to a better quality of life for patients affected by brain metastases.     

Solitary liver metastasis from Hürthle cell thyroid cancer: a case report and review of the literature

Metastasis to the liver from thyroid cancer is a rare event with a reported frequency of 0.5%. Metastatic liver involvement from differentiated thyroid cancer (DTC) is nearly always multiple or diffuse and usually found along with other distant metastases (lung, bone and brain). The authors describe a patient with a solitary liver metastasis from Hürthle cell thyroid cancer, which appeared during long-term follow-up. The lesion was diagnosed by progressive increase of thyroglobulin in the serum and imaged with I-131 whole body scan, ultrasonography, magnetic resonance imaging (MRI) and F-18 fluoro-deoxyglucose positron emission tomography (FDG-PET) scan. For patients with a Tg level above some arbitrary limit, the administration of a large dose (3.7-5.5 GBq; 100-150 mCi) of I-131, in order to obtain a highly sensitive Tx whole body scan (WBS), remains the best diagnostic strategy. However, on very rare occasions, physiological enteric radioactivity can hide possible abdominal lesions and further indepth studies, such as FDG-PET scans, are sometimes necessary.     

Positron emission tomography for the detection of metastases of differentiated thyroid carcinoma

OBJECTIVE: To show the value of positron emission tomography (PET) with 18-F-fluorodeoxyglucose (18-FDG) for the detection of metastases of differentiated thyroid carcinoma in selected patients. PATIENT HISTORIES: There were four patients, who had undergone total thyroidectomy for papillary (two) or follicular thyroid carcinoma (two). All patients had subsequent treatment with (131)iodine. Three patients had an increasing serum concentration of thyroglobulin, one patient had antibodies against thyroglobulin. A diagnostic (131)iodine scintigraphy was negative in two patients, and uncertain in two patients. Positron emission tomography was performed about 45 min after administration of 10 mCi 18-F-fluorodeoxyglucose. In three patients PET showed uptake in the cervical region, caused by lymph node metastases in two (confirmed by neck dissection) and recurrent tumor on the trachea in one patient (confirmed by surgery). In the fourth patient uptake of 18-FDG was seen in the neck and in both lungs. This led to discontinuation of treatment with (131)iodine because the lung metastases did not accumulate (131)iodine. DISCUSSION: In selected patients with differentiated thyroid carcinoma with an increasing serum concentration of thyroglobulin, PET is an important diagnostic option when scintigraphy with (131)iodine is negative or uncertain. In the four presented case histories, the results of PET led to a therapeutic decision: surgery in three patients and discontinuation of (131)iodine in one patient. The development of guidelines for the use of PET in the diagnosis of recurrent thyroid cancer is discussed.     

Adrenal metastasis of a papillary thyroid cancer

Adrenal metastases of the papillary thyroid carcinoma (PTC) are very rare. We report one case. A 63-year-old woman had undergone 15 years earlier left lobo-ishmectomy for a papillary thyroid cancer (PTC) and 7 years earlier right adrenalectomy for a tumor. Histologic examination showed a benign cortical tumor. In 1999, when the patient was admitted for worsening of glycemic control, a recurrence of the adrenal mass was detected. According to the hormone evaluation it was a non-functional tumor. Adrenalectomy was performed in June 2002 because the patient had initially declined surgery. Histologic examination and thyroglobulin immunochemistry identified metastatic PTC. Re-reading the histology slide of the first adrenalectomy agreed with the diagnosis. Thyroidectomy was completed in March 2003. Although iodine-131 therapy and thyroxine treatment were given, bone metastases were detected in August 2004. PTC usually spreads to the cervical and mediastinal lymph nodes. Distant spread may occur to bone or lung, but exceptionally to the adrenal gland. The adrenal localization is often associated with lung or bone metastasis. In our patient, the adrenal metastasis remained isolated for many years. It has been reported that survival rate decreases considerably after appearance of a distant metastasis. Although given delayed radical treatment, our patient remained alive 13 years after.     

Does undetectable basal Tg measured with a highly sensitive assay in the absence of antibodies and combined with normal ultrasonography ensure the absence of disease in patients treated for thyroid carcinoma?

It has been proposed that, in patients treated for well-differentiated thyroid carcinoma, undetectable basal thyroglobulin (Tg) levels measured with a highly sensitive assay in the absence of anti-thyroglobulin antibodies (TgAb) and combined with negative neck ultrasonography (US) ensured the absence of disease. We report a series of five patients with well-differentiated (papillary) carcinoma submitted to total thyroidectomy with apparently complete tumor resection, followed by remnant ablation with (131)I (100-150 mCi), who had no distant metastases upon initial post-therapy whole-body scanning. When tumor recurrence or persistence was detected, these patients presented undetectable basal Tg (0.1 ng/mL) in the absence of TgAb, and US showed no anomalies. Two patients had lymph node metastases, one had mediastinal metastases, bone involvement was observed in one patient, and local recurrence in one. We conclude that further studies are needed to define in which patients undetectable basal Tg (negative TgAb) combined with negative US is sufficient, and no additional tests are required.     

Advanced insular thyroid carcinoma in a fourteen-year-old girl: twenty-four years of follow-up.

Insular thyroid carcinoma has become a separate entity among thyroid malignancies. It is regarded as intermediate in aggressiveness between well-differentiated and anaplastic thyroid carcinomas. Reports on the clinical course of children with insular thyroid carcinoma are rare. We report the case of a 14-year-old girl who was admitted to our thyroid outpatient ward in 1975 with a scintigraphic cold thyroid nodule and multiple enlarged cervical lymph nodes. Chest radiography showed metastases in both lungs. After total thyroidectomy and, central and modified unilateral radical neck dissection, the girl was given a dose of 80 mCi 131I. Posttherapeutic scan demonstrated diffuse tracer uptake in both lungs. A second dose of 200 mCi 131I was administered 4 months later and another dose of 150 mCi 131I in July 1976. Subsequently, whole-body scans showed inconspicuous tracer distribution and chest x-rays were normal. The patient was treated with levothyroxine and followed until 1982, when she left Vienna. In 1999, the patient was contacted for reexamination. She has been well and had had two healthy children. The patient was taking 150 microg levothyroxine daily; she had a normal TSH value and her thyroglubulin was 0.3 ng/mL. Chest radiography and sonography of the neck showed no pathological findings. The paraffin sections of the patient's tumor were reexamined in 1999 and demonstrated the histologic characteristics of a poorly differentiated insular thyroid carcinoma (pT4a, pN1a, M1). These findings demonstrate that even in advanced stages, insular thyroid carcinoma treatment can be successful.     

Cervicomediastinal magnetic resonance imaging in persistent or recurrent papillary thyroid carcinoma: clinical use and limits.

Cervicomediastinal magnetic resonance imaging (MRI) was evaluated in 13 consecutive persistent or recurrent papillary thyroid carcinoma (PTC) patients, previously treated by total thyroidectomy and radioiodine ablation. All had elevated thyroglobulin (Tg) levels and were therefore submitted to a new therapeutic radioiodine dose followed by a posttherapeutic whole-body scan (131I-WBS) and subsequent MRI. Patients with known distant metastases were excluded from the study. Group 1 included 7 patients with a negative 131I-WBS, whereas cervical and/or mediastinal 131I-uptake was evidenced in the other 6 patients (group 2). MRI was thus compared to 131I-WBS, and additionally in 8 reoperated cases, to histology. MRI was positive in 11 of 13 (85%) patients, corresponding to 23 of 55 (41.8%) histologically confirmed sites. In group 1, MRI was positive in 5 of 7 patients, with a sensitivity of 47% (15/32 histologically positive sites), allowing appropriate indication of surgery: 4 neck surgery, and 1 mediastinal dissection because of too distant lymph node foci. In group 2, MRI always showed more localization than 131I-WBS; histology was obtained in 3. Because all the foci located in the mediastinal area (0.8 to 1.8 cm) were histologically confirmed (7/7 sites), MRI avoided underestimation of surgery in the 8 reoperated patients. However, additional images were also observed corresponding to a normal thymus, a small neuroma or inflammatory lymph nodes, but pretracheal and very small nodes (less than 0.5 cm) were missed. In conclusion, although less specific than radioiodine scintigraphy, MRI can detect local persistent or recurrent PTC, and seems particularly effective for evaluation of mediastinal involvement.     

Multiple pulmonary neoplasia positive for thyroglobulin

We present, for the first time, a case of carcinoid metastatic pulmonary tumor positive for thyroglobulin. A 73-yr-old woman diagnosed with metastases of probable thyroid carcinoma, manifested by a mediastinic mass and multiple pulmonary nodules positive for radioiodine (I131). Histological analysis showed typical findings of carcinoid tumor with positive immunohistochemistry for neuron-specific enolase, synaptophysin and thyroglobulin, and negative for chromogranin and calcitonin. We underline the exceptional finding of positive reaction for thyroglobulin, and discuss difficulties in differential diagnosis between metastatic differentiated thyroid and carcinoid neoplasms.     

Should ‘low‐risk’ thyroid cancer patients with residual thyroglobulin be re‐treated with iodine 131?

OBJECTIVE: The American consensus statement on patients with low-risk thyroid cancer, published in 2003, suggests repeat (131)I therapy if the thyroglobulin value is elevated at first follow-up. We evaluated this strategy in our practice. METHODS: Among 407 patients with thyroid cancer who had total thyroidectomy and (131)I ablation between January 2000 and December 2003, 12 patients with stage I thyroid cancer (any tumour (T), any node (N), metastasis (M)0 if < 45 years or T1, N0, M0 if > 45 years), were re-treated on the basis of their thyroglobulin level at first follow-up. Mean patient age was 32.8 years. None of them had a T4 tumour. Thyroglobulin levels after thyroid hormone withdrawal 'off-T4' ranged between 4.5 and 251 ng/ml (median 8). One to four courses of 3.7 GBq (131)I were given. RESULTS: Three patients had a negative (131)I therapy scan and an uneventful course. Two patients had slight residual uptake only in the thyroid bed and negative ultrasound examination. Four patients had isolated (131)I uptake in the mediastinal region. No abnormalities were found on complementary mediastinal imaging. This finding was interpreted as benign (131)I thymic uptake. The last three patients also had mediastinal thymic uptake associated with a slight thyroid bed uptake. One patient had a gradual increase in the thyroglobulin level, and underwent resection of nonfunctioning neck lymph nodes. Thyroglobulin levels declined in all other patients. CONCLUSIONS: No distant lesions were found in a group of young 'low-risk' thyroid cancer patients given empirical (131)I therapy for residual thyroglobulin. When blind (131)I therapy shows no uptake, or uptake limited to the thymus, (131)I therapy should not be repeated. The authors also briefly discuss the hypothesis that enhanced thymus might be a source of benign thyroglobulin secretion.     

Failure to use measurement of megalin secretory components complexed with serum thyroglobulin as a tool to identify metastases after surgery in papillary thyroid cancer

When thyroid follicles are intact, some colloidal thyroglobulin (Tg) reaches the circulation by megalin-mediated transcytosis and is to various extents complexed with megalin secretory components. In contrast, in papillary thyroid cancer (PTC), serum Tg is not complexed with megalin because it is directly secreted by tumor cells. Here we attempted to use measurement of megalin secretory components to distinguish PTC patients with thyroid remnant plus metastases from those with thyroid remnant only, after thyroidectomy and before 131I ablation. Tg values in anti-Tg antibodies (TgAb)-free sera from 5 PTC patients with thyroid remnant plus metastases and 12 PTC patients with thyroid remnant only were measured following pre-adsorption with uncoupled protein A beads or with protein A beads coupled with antimegalin antibodies. The degree of Tg pre-adsorption with antimegalin antibodies was minimal, with no substantial differences between the two groups. Thus, we concluded that measurement of megalin secretory components is unlikely to be useful to identify the origin of serum Tg in PTC patients after thyroidectomy.