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Background: Lingual thyroid is a rare abnormality of thyroid development that is usually treated conservatively with levothyroxine replacement. Rarely, it becomes large enough to cause obstructive symptoms in the oral cavity, requiring definitive treatment., Patient Findings: This study reports on three patients with lingual thyroid treated with radioactive iodine-131 ((131)I) with successful radioablation of their ectopic thyroid tissues. Measurement of 24-hour radioactive iodine uptake within thyroidal tissues and hybrid single-photon emission computed tomography/computed tomography imaging using either iodine-123 or technetium-99m pertechnetate scans were performed in all patients demonstrating the location and size of lingual thyroid and absence of an orthotopic thyroid gland., Summary: The aim of this study was to describe nonsurgical management of obstructive lingual thyroid tissue with (131)I therapy for lingual thyroid radioablation. Patients were prepared with a low-iodine diet and levothyroxine withdrawal prior to radioablation for optimizing (131)I uptake in ectopic thyroid tissues. Hybrid single-photon emission computed tomography/computed tomography measurement of anatomic size of lingual thyroid tissue and radioactive iodine uptake guided the selection of therapeutic doses, resulting in administration of 10.7, 17.5, and 15.4 mCi of (131)I, respectively. There were no post-therapy complications, and clinical follow-up demonstrated resolution of obstructive oropharyngeal symptoms., Conclusions: Ectopic lingual thyroid tissue is rarely associated with obstructive oropharyngeal symptoms due to progressive enlargement. Radioiodine therapy with (131)I is an effective treatment modality for ablation of ectopic thyroid tissue as an alternative to surgery.

Radioiodine imaging has a well-established role in depicting metastatic disease after thyroidectomy in patients with well-differentiated thyroid cancer. Uptake of radioiodine in thyroid metastases depends on expression of sodium-iodide symporter (NIS) by tumor tissues. However, because radioiodine may also accumulate in normal structures and tissues, it is important to distinguish physiologic radioiodine activity from metastatic disease. Furthermore, secretions that contain radioiodine may also simulate pathologic uptake. A spectrum of physiologic distributions, normal variants, and benign mimics of disease have been described in the literature; yet, even when armed with a comprehensive knowledge of these patterns, interpreting radiologists and nuclear physicians may still encounter diagnostic uncertainty. Single-photon emission computed tomography (SPECT) with integrated computed tomography (CT) is a novel technology that, when applied to diagnostic iodine 123 or iodine 131 ((131)I) radioiodine scintigraphy, may accurately localize and help distinguish benign mimics of disease, with the potential to alter the management plan. SPECT/CT is increasingly being used with radioiodine scintigraphy to evaluate patients with thyroid cancer and shows promise for improving imaging specificity and reducing false-positive results.

Context: The utility of preablation radioiodine scans for the management of differentiated thyroid cancer remains controversial., Objective: To determine the contribution of preablation Iodine 131 (131-I) planar with single-photon emission computed tomography/computed tomography (SPECT/CT; diagnostic [Dx] scans) to differentiated thyroid cancer staging., Design: Prospective sequential series at university clinic., Methods: Using American Joint Committee on Cancer (AJCC) tumor, node, metastasis (TNM) staging, seventh edition 320 patients post-total thyroidectomy were initially staged based on clinical and pathology data (pTN) and then restaged after imaging (TNM). The impact of Dx scans with SPECT/CT on N and M scores, and TNM stage, was assessed in younger, age <45 years, n = 138 (43%), and older, age ≥ 45 years, n = 182 (57%) patients, with subgroup analysis for T1a and T1b tumors., Results: In younger patients Dx scans detected distant metastases in 5 of 138 patients (4%), and nodal metastases in 61 of 138 patients (44%), including unsuspected nodal metastases in 24 of 63 (38%) patients initially assigned pathologic (p) N0 or pNx. In older patients distant metastases were detected in 18 of 182 patients (10%), and nodal metastases in 51 of 182 patients (28%), including unsuspected nodal metastases in 26 of 108 (24%) patients initially assigned pN0 or pNx. Dx scans detected distant metastases in 2 of 49 (4%) T1a, and 3 of 67 (4.5%) T1b patients., Conclusions: Dx scans detected regional metastases in 35% of patients, and distant metastases in 8% of patients. Information acquired with Dx scans changed staging in 4% of younger, and 25% of older patients. Preablation scans with SPECT/CT contribute to staging of thyroid cancer. Identification of regional and distant metastases prior to radioiodine therapy has significant potential to alter patient management.

Medullary thyroid cancer (MTC) arises from parafollicular C cells and is an elusive tumor to image. It occurs as a sporadic neoplasm in 70-80% of cases and is hereditary in 20-30% because of germline mutations of the rearranged during transfection proto-oncogene. Successful disease management relies on accurate staging. Tumor secretory biomarkers are highly sensitive to a disease; however, despite a wide variety of radiopharmaceuticals for molecular imaging that take advantage of hybrid SPECT/CT and PET/CT fusion imaging, imaging of MTC is still problematic. After initial surgical resection, the limited sensitivity of localization of small locoregional disease and the inability to detect early liver metastases hamper the success of later surgical approaches. F-fluorodeoxyglucose PET has been used to detect MTC recurrences with modest success and may be best suited for only a small subset of more biologically aggressive MTCs. Recent developments in PET imaging with novel radiopharmaceuticals targeting specific cellular processes of MTC offer increased sensitivity for identifying recurrence, assessing prognosis, and guiding selection of optimal therapies.

Background: Primary thyroid lymphoma is an uncommon neoplasm frequently associated with lymphocytic thyroiditis (LT). Once the pathologic diagnosis of primary thyroid lymphoma is established, imaging plays an important role in tumor staging and evaluating treatment response. The present case discusses the role of fluorodeoxyglucose positron emission tomography (18F-FDG PET)/computed tomography (CT) in this clinical setting along with the potential diagnostic challenges., Patient Findings: A 44-year-old man with a history of LT and hypothyroidism presented with an enlarging goiter. Initial imaging evaluation showed markedly enlarged gland with bilateral cervical and mediastinal adenopathy. Histopathologic evaluation confirmed the diagnosis of primary thyroid lymphoma on a background of LT. An 18F-FDG PET/CT revealed increased uptake in the gland and lymph nodes. Follow-up 18F-FDG PET/CT after chemotherapy showed interval decrease in FDG uptake in the thyroid gland associated with interval decrease in the size and metabolic activity of the cervical and superior mediastinal lymph nodes., Conclusions: The frequent association of LT with primary thyroid lymphoma and the overlap of their clinical and pathologic findings pose a significant diagnostic challenge. While other imaging techniques are helpful in evaluating anatomic local and regional extent of primary thyroid lymphoma, 18F-FDG PET/CT can be of an added value in evaluating its metabolic activity and detecting regional and distant disease as well as in assessing response to treatment.

Background: In general, thyroid carcinomas, when they behave aggressively, metastasize to lungs and occasionally to bone and brain. Metastases to other organs are distinctly unusual. Renal metastases have been reported in only 10 patients. Here we report, to the best of our knowledge, the first patient with Hurthle cell thyroid cancer and renal metastasis. The evaluation of this patient was enhanced by utilizing a variety of imaging techniques., Summary: The patient was a 75-year-old man who had a history of a total thyroidectomy 9 years previously for a right thyroid lobe Hurthle cell carcinoma. He postoperatively received 150 mCi (5550 MBq) of 131-I therapy and was maintained on thyrotropin suppressive therapy with levothyroxine. He presented to us with a recent history of a progressively enlarging left neck mass. The serum thyroglobulin was elevated to 1183 ng/mL. Multimodality imaging with fluorodeoxyglucose positron emission tomography-computed tomography, magnetic resonance imaging, and Somatostatin receptor scintigraphy with single photon emission computed tomography (SPECT)-computed tomography revealed numerous foci in the skeleton and right kidney. Anatomic imaging characteristics favored a primary renal cell cancer with the additional evidence of renal vein invasion and thrombosis. Histology later revealed a metastatic renal Hurthle cell cancer with positive thyroglobulin stains. Several of the skeletal foci responded partially to cryoablative therapy. The patient refused noncurative Somatostatin analog therapy. He is alive and doing well clinically., Conclusion: The management of thyroid cancers in high-risk groups, such as our patient, frequently requires expert management by the use of novel multimodality imaging and therapeutic techniques.

Medullary thyroid carcinoma (MTC) is a rare neuroendocrine tumor originating in the parafollicular cells (C cells) of the thyroid and secretes both calcitonin and carcino-embryonic antigen (CEA). Genetic and biochemical testing allow early pre-clinical identification of familial forms. Sporadic MTC usually presents as a solitary thyroid nodule; the diagnosis can be made preoperatively by fine-needle aspiration or by calcitonin assay, though it is usually established at the time of surgery. In the diagnostic assessment of MTC, nuclear medicine imaging provides its contribution mainly in the post-operative work-up to detect residual/recurrent tumor. For such purpose a number of radiopharmaceuticals, which take advantage of the specific expression of receptors (the somatostatin analogue (111)In-octreotide), hormone transporters (radiolabelled MIBG) or molecular targets (radiolabelled anti-CEA monoclonal antibodies) by MTC lesions are available; these tracers may be used also for the palliative treatment of advanced MTC. Interesting perspectives for MTC imaging are offered by PET radiopharmaceuticals.

Background and Aim: Papillary thyroid carcinoma (PTC) is universally regarded as a curable malignancy with a favorable prognosis. However, a minority of patients may present, or subsequently develop, locoregional and distant metastases that may adversely affect survival. The value of the various staging methods is complicated by different approaches to diagnostic, therapeutic and follow-up strategies. We aimed at assessing the prognostic factors and survival rate in a large cohort of patients treated and followed up in the same center., Materials and Methods: A total of 1858 patients with PTC operated on by the same surgeon, and followed in the same center over a period of 35 years, were included. Total thyroidectomy was performed in the majority of patients after I-131 diagnostic scans and thyroglobulin assays. When the latter 2 were positive, therapy with I-131 was given. Follow-up was performed periodically and further therapy doses were administered when necessary. All patients were maintained on life-long thyroxine., Results: Ninety-three patients (5%) developed evidence of locoregional or distant metastases after an average follow-up period of 7.9 years (range 1.53-30.5 years). Univariate analysis showed all variables (except for gender) to be significantly correlated with disease recurrence and survival. Multivariate analysis showed 4 variables to be significant and independent prognostic factors: patient age at first treatment, extent of disease, extent of surgery, and the presence of I-131 positive metastases., Discussion and Conclusion: Our data agree with other scoring systems in that patient age at first treatment and the extent of disease are significant and independent prognostic factors. However, and at variance with other methods, we found that the extent of primary surgery and the presence of I-131 positive or negative metastases have similar prognostic significance. In high risk patients, total thyroidectomy and lymphadenectomy followed by I-131 treatment and TSH-suppressive hormonal therapy are recommended.

Purpose: The aim of this study was to establish the clinical efficacy of the "low sestamibi dose" (LSD) protocol to perform thyroid and parathyroid radioguided surgery in a large series of patients homogeneously studied and operated on by the same surgeon. The LSD protocol was initially developed in our center to cure primary hyperparathyroid (PHPT) patients with a high likelihood of a solitary parathyroid adenoma (PA) by minimally invasive radioguided surgery (MIRS). Since then, the same protocol has been applied to differentiated thyroid cancer (DTC) patients with 131I-negative, but sestamibi-positive, locoregional recurrent disease in order to obtain radical radioguided extirpation of tumoral lesions at reoperation., Study Design: We reviewed the clinical charts of 453 consecutive patients referred at the surgical department at Padova University (Padova, Italy) to investigate a PHPT or a DTC recurrence: 336 patients (74.2%) met the inclusion criteria for radioguided surgery, and these patients were analyzed for the aim of this study. There were 298 patients affected by PHPT with a high likelihood of a solitary sestamibipositive PA and 38 DTC patients affected by 131I-negative, but sestamibi-positive, locoregional recurrence. All patients underwent a preoperative imaging work-up, including sestamibi scintigraphy (doubletracer subtraction scan in PHPT patients and single-tracer, wash-out scan in DTC patients) and high-resolution neck ultrasonography (US). The LSD protocol we developed consists of the intravenous injection of a very low (1 mCi) sestamibi dose in the operating theater just 10 minutes before commencing intervention for the purpose of radioguided surgery only. At variance with the traditional "high (20-25 mCi) sestamibi dose (HSD)" protocol in which imaging and radioguided surgery are obtained in the same day, in the LSD protocol, imaging and radioguided surgery are performed in different days. The LSD protocol allows some advantages over the HSD protocol: (1) more time for acquiring and interpreting preoperative imaging (planar scintigraphy, single-photon emission computed tomography [SPECT], US); (2) an accurate selection of patients to whom MIRS is offered, especially in countries where the prevalence of nodular goiter with sestamibi-avid thyroid nodules (exclusion criteria for MIRS) is relatively high, as in mid-south-European countries; (3) it facilitates the work planning in the operating theater (bilateral neck exploration requires an operating time of at least double to that of MIRS); and (4) the radiation exposure dose to operating theater personnel is very low-substantially negligible, using the LSD protocol: This aspect assumes great importance in countries where radioproteximetric rules are stringent, as in Europe., Results: PHPT patients. MIRS was successfully performed by a 1.5-2-cm skin incision in 287 of 298 PHPT patients (96.3%) in whom such an approach was scheduled on the basis of preoperative imaging, including 41 of 57 patients (71.9%) who had previously received thyroid or unsuccessful parathyroid surgery in another center. No case of major intraoperative complication was recorded. No case of persistent or recurrent PHPT was observed during postsurgical follow-up. DTC patients. A total of 79 metastatic lesions were intraoperatively detected by the gamma probe and successfully removed (68 of them had been correctly visualized at preoperative sestamibi scintigraphy). During subsequent follow-up, 18 patients (72%) were considered disease-free, whereas 7 had persistent disease (increased serum thyroglobulin levels). The radiation exposure dose to the surgeon using the LSD protocol was 1.2 uSi/hour, that is, 20-30-fold lower than that delivered with the HSD protocol used for PHPT patients and with the 131I protocol used for DTC patients with recurrence., Conclusions: On the basis of our data, it can be concluded that the LSD protocol is a safe and effective protocol to perform in both MIRS in PHPT patients and radioguided reoperation in DTC patients with 131I-negative recurrence. Furthermore, from a radioproteximetric point of view, in comparison with other radioguided protocols used for the same purposes, the LSD protocol minimizes the radiation-exposure dose to the surgeon and operating theater personnel.