Papillary Thyroid Cancer, Small Cell Lung Cancer, and Parathyroid Adenoma Synchronously Visualized on 99m Tc-MIBI SPECT/CT in a Patient With Hyperparathyroidism : Comparison With 18 F-FDG PET/CT.

ABSTRACT: 99m Tc-MIBI scintigraphy is a nuclear medicine imaging modality commonly used for the preoperative localization of parathyroid adenomas in patients with hyperparathyroidism. In addition, 99m Tc-MIBI can also be used for imaging various tumors due to its unique mechanism of intracellular accumulation. Here, we introduced a case of a single 99m Tc-MIBI SPECT/CT simultaneously visualized two different malignant tumors, such as papillary thyroid cancer and small cell lung cancer, along with a parathyroid adenoma in a patient with hyperparathyroidism. The clinical usefulness of 99m Tc-MIBI SPECT/CT was also explored by comparing it with 18 F-FDG PET/CT among the three tumors.

Ultrasound-Guided Radiofrequency Ablation in Tertiary Hyperparathyroidism: A Prospective Study.

OBJECTIVE: To prospectively evaluate the outcomes of ultrasound (US)-guided radiofrequency ablation (RFA) in tertiary hyperparathyroidism (THPT). MATERIALS AND METHODS: Patients with THPT underwent RFA between September 2017 and January 2022. Laboratory parameters, including serum intact parathyroid hormone (iPTH) levels, were monitored for 48 months after RFA and compared with the levels at baseline. Complications related to RFA and changes in hyperparathyroidism-related clinical symptoms were recorded before and after RFA. RESULTS: A total of 42 patients with THPT were recruited for this study. Ultimately, 36 patients with renal failure and 2 patients who underwent successful renal transplantation (male:female, 17:21; median age, 54.5 years) were enrolled. The follow-up time was 21.5 ± 19.0 months in the 36 patients with renal failure. In these 36 patients, iPTH levels were significantly decreased to 261.1 pg/mL at 48 months compared with the baseline value of 1284.9 pg/mL (P = 0.012). Persistent hyperparathyroidism, defined as iPTH levels maintained at > 585.0 pg/mL for 6 months after treatment, occurred in 4.0% of patients (1/25). Recurrent hyperparathyroidism, defined as iPTH levels > 585.0 pg/mL after 6 months, were 4.0% (1/25) and 0.0% (0/9) at 6 months and 4 years after treatment, respectively. In two patients with THPT after successful renal transplantation, iPTH decreased from the baseline value of 242.5 and 115.9 pg/mL to 171.0 and 62.0 pg/mL at 6 months after treatment. All complications resolved within 6 months of ablation without medical intervention, except in 10.5% (4/38) patients with permanent hypocalcemia. The overall symptom recovery rate was 58.8% (10/17). The severity scores for bone pain, arthralgia, and itchy skin associated with hyperparathyroidism improved after treatment (P < 0.05). CONCLUSION: US-guided RFA is an effective and safe alternative to surgery in the treatment of patients with TPTH and improves hyperparathyroidism-related clinical symptoms.

Synchronous Ectopic Thyroid Gland and Ectopic Parathyroid Adenoma on 99mTc-Sestamibi Scintigraphy and Correlative Imaging.

99mTc-sestamibi scintigraphy localizes parathyroid adenoma as a persistent focus of uptake on delayed images, whereas thyroid glands in normal or ectopic locations are seen on only early images and wash out on delayed images. We report a case of absence of eutopic neck thyroid activity and synchronous ectopic lingual thyroid and mediastinal parathyroid adenoma on scintigraphy confirmed with CT.

Preoperative imaging for hyperparathyroidism often takes upper parathyroid adenomas for lower adenomas.

We retrospectively evaluated how accurately preoperative imaging localizes parathyroid adenoma in superior versus inferior parathyroids. Over 6 years, 104 patients with primary hyperparathyroidism underwent parathyroid surgery in a single centre. Of these, 103 underwent ultrasound, 97 [99mTc]pertechnetate/MIBI SPECT/CT and 30 [18F]fluorocholine (FCH) PET/CT. One patient with a unilateral double adenoma was excluded from the analysis. Surgical findings with histopathologic confirmation of adenoma were used as the standard. Ultrasound misjudged 5 of 48 detected lower adenomas as upper, but 14 of 29 upper adenomas as lower (error rate 10 vs 48%, p = 0.0002). The corresponding error rates for [99mTc]pertechnetate/MIBI SPECT/CT were 3 versus 55% (p = 0.000014), and for [18F]FCH PET/CT 17 versus 36% (p = 0.26). Our results suggest that about half of the superior parathyroid adenomas which are detected, are erroneously assigned to the inferior position by both ultrasound and SPECT/CT imaging whereas the opposite mistake is significantly less frequent with ultrasound and SPECT/CT.

Clinical application of 18F-FCH PET/CT in the diagnosis and treatment of hyperparathyroidism.

Objective: We evaluated the difference in parathyroid visualization on 18F-FCH PET/CT images obtained at 5 and 60 min, and quantitatively analyzed the mode of FCH uptake at different time points, to determine the best imaging time for FCH PET/CT. Methods: This retrospective study included 73 patients with hyperparathyroidism (HPT) who underwent 18F-FCH PET/CT imaging between December 2017 and December 2021. The diagnostic efficiency of 5- and 60-min dual time point imaging for the diagnosis of hyperparathyroidism and parathyroid adenoma and hyperplasia, were compared using visual and quantitative analyses. Results: Dual-time 18F-FCH PET/CT imaging visual analysis had diagnostic value for HPT. The receiver operating characteristic curve of PET/CT quantitative parameters for the diagnosis of HPT and lesions showed that the parathyroid/thyroid SUVmax ratio for 60-min imaging had a higher sensitivity and specificity (based on patient, sensitivity: 90.90% and specificity: 85.71%; based on focus, sensitivity: 83.06% and specificity: 85.71%) compared to that for 5-min imaging. PET/CT quantitative parameters can distinguish parathyroid adenoma and hyperplasia. The 60-min parathyroid SUVmax value had the highest diagnostic value (cutoff: 3.945; area under the curve: 0.783). Conclusion: The quantitative parameters of 60min 18F-FCH PET/CT have more advantages in aiding in the pathologica diagnosis and clinical treatment of HPT.

Parathyroid Imaging.

Primary hyperparathyroidism (1° HPT) is a relatively common endocrine disorder usually caused by autonomous secretion of parathormone by one or several parathyroid adenomas. 1° HPT causing hypercalcemia, kidney stones and/or osteoporosis should be treated whenever possible by parathyroidectomy. Accurate preoperative location of parathyroid adenomas is crucial for surgery planning, mostly when performing minimally invasive surgery. Cervical ultrasonography (US) is usually performed to localize parathyroid adenomas as a first intention, followed by 99mTc- sestamibi scintigraphy with SPECT/CT whenever possible. 4D-CT is a possible alternative to 99mTc- sestamibi scintigraphy. Recently, 18F-fluorocholine positron emission tomography/computed tomography (18F-FCH PET/CT) has made its way in the clinics as it is the most sensitive method for parathyroid adenoma detection. It can eventually be combined to 4D-CT to increase its diagnostic performance, although this results in higher dose exposure to the patient. Other forms of hyperparathyroidism consist in secondary (2° HPT) and tertiary hyperparathyroidism (3° HPT). As parathyroidectomy is not usually part of the management of patients with 2° HPT, parathyroid imaging is not routinely performed in these patients. In patients with 3° HPT, total or subtotal parathyroidectomy is often performed. Localization of hyperfunctional glands is an important aid to surgery planning. As 18F-FCH PET/CT is the most sensitive modality in multigland disease, it is the preferred imaging technic in 3° HPT patients, although its cost and availability may limit its widespread use in this setting.

Pitfalls of DualTracer 99m-Technetium (Tc) Pertechnetate and Sestamibi Scintigraphy before Parathyroidectomy: Between Primary-Hyperparathyroidism-Associated Parathyroid Tumour and Ectopic Thyroid Tissue.

Diagnosis of primary hyperparathyroidism (PHP) is based on blood assessments in terms of synchronous high calcium and PTH (parathormone), but further management, particularly parathyroid surgery that provides the disease cure in 95-99% of cases, requires an adequate localisation of the parathyroid tumour/tumours as the originating source, with ultrasound and 99m-Technetium (99m-Tc) sestamibi scintigraphy being the most widely used. We aimed to introduce an adult female case diagnosed with PHP displaying unexpected intra-operatory findings (ectopic thyroid tissue) in relation to concordant pre-operatory imaging modalities (ultrasound + dual-phase 99m-Tc pertechnetate and sestamibi scintigraphy + computed tomography) that indicated bilateral inferior parathyroid tumours. A sudden drop in PTH following the removal of the first tumour was the clue for performing an extemporaneous exam for the second mass that turned out to be non-malignant ectopic thyroid tissue. We overviewed some major aspects starting from this case in point: the potential pitfalls of pre-operatory imaging in PHP; the concordance/discordance of pre-parathyroidectomy localisation modalities; the need of using an additional intra-operatory procedure; and the clues of providing a distinction between pathological parathyroids and thyroid tissue. This was a case of adult PHP, whereas triple localisation methods were used before parathyroidectomy, showing concordant results; however, the second parathyroid adenoma was a false positive image and an ectopic thyroid tissue was confirmed. The pre-operatory index of suspicion was non-existent in this patient. Hybrid imaging modalities are most probably required if both thyroid and parathyroid anomalies are suspected, but, essentially, awareness of the potential pitfalls is mandatory from the endocrine and surgical perspectives. Current gaps in imaging knowledge to guide us in this area are expected to be solved by the significant progress in functional imaging modalities. However, the act of surgery, including the decision of a PTH assay or extemporaneous exam (as seen in our case), represents the key to a successful removal procedure. Moreover, many parathyroid surgeons may currently perform 4-gland exploration routinely, precisely to avoid the shortcomings of preoperative localisation.

Lipoadenoma of the parathyroid: characteristics of a rare cause of hyperparathyroidism.

Parathyroid Lipoadenoma (PLA) contains abundant mature adipose tissue and is a rare cause of hyperparathyroidism. This study aimed to investigate the clinical features of PLA in nine patients with primary hyperparathyroidism, including two men and seven women, with ages ranging from 45-84 years (median 60 years). PLA accounted for 0.5% of all parathyroid tumors during the study period. One patient presented with anorexia due to hypercalcemia; however, the other eight patients were asymptomatic. The median preoperative serum intact-parathyroid hormone (iPTH) and calcium levels were 143 pg/mL (range, 102-378) and 10.8 mg/dL (range, 10.3-11.3), respectively. PLA was difficult to identify using ultrasonography (US) as it appears as a moderately hyperechoic nodule and is difficult to distinguish from the surrounding adipose tissues. Only 33% of the lesions (three out of nine lesions) were accurately identified. However, they could be distinctly differentiated from the surrounding tissue using computed tomography (CT). All PLAs were also detected using the sesta-methoxyisobutylisonitrile single-photon emission-computed tomography (SPECT). All the patients were treated by a single gland extirpation. The median size and weight of the PLA were 14 mm (range, 10-22) and 567 mg (range, 200-1,533), respectively. In conclusion, the clinical manifestations of PLA are similar to those of ordinal parathyroid adenomas, except for their unique US and CT images. PLA should be considered as a potential etiologic factor in cases of hyperparathyroidism when the lesions are demonstrated as hyperechoic nodules or unidentified by US but detected by CT or SPECT imaging.

Increased 99mTc-Sestamibi Activity in Giant Cell Tumor of Bone.

ABSTRACT: A 99mTc-sestamibi parathyroid scintigraphy was performed in a 27-year-old woman to evaluate possible hyperparathyroidism. The images did not identify any parathyroid abnormality. However, an intense activity was noted in the proximal left upper extremity, which was confirmed as giant cell tumor of the proximal left humerus by pathological examination.

Central odontogenic fibroma in association with brown tumor of hyperparathyroidism in a patient with neurofibromatosis type 1.

We present a patient with bone abnormalities and a myriad of lesions secondary to his redeveloping renal failure and neurofibromatosis type 1 (NF1). A 21-year-old male renal transplant recipient with NF1 presented with painless masses and large, irregular radiolucent lesions in the maxilla and mandible. After histologic examination, the lesion was diagnosed as a central odontogenic fibroma (COdF) in association with a central giant cell lesion, most consistent with brown tumor of hyperparathyroidism. The bone changes were interpreted to be highly suggestive of renal osteodystrophy. Around 30 cases of hybrid central giant cell granuloma-like lesion in association with central odontogenic fibroma have been reported. This, to our knowledge, is the first reported case of brown tumor in association with COdF. Our case provides further evidence of the giant cell component as the initiating entity in these hybrid lesions.

Usefulness of PET/CT with Carbon-11-Labeled Methionine in the Diagnosis of Tertiary Hyperparathyroidism.

Introduction: Tertiary hyperparathyroidism (tHP) may develop in patients treated with hemodialysis or peritoneal dialysis. Parathyroidectomy may result in a significant reduction in the severity of symptoms. For the effective surgical treatment of hyperparathyroidism, proper localization of the parathyroid glands prior to surgery is essential. The sensitivity of scintigraphy in the diagnosis of tHP is lower than in the diagnosis of primary hyperparathyroidism. In recent years, positron emission tomography (PET/CT) has been gaining importance, usually as a complementary technique. Aim: The aim of this study was to determine the usefulness of PET/CT with [11C]MET in the preoperative localization diagnosis of patients with tertiary hyperparathyroidism caused by chronic kidney disease, in whom first-line diagnostic methods did not allow the localization of pathologically parathyroid glands. Material and methods: The study was conducted in a group of 19 adult patients with severe tHP who were resistant or intolerant to non-invasive treatment, with negative results of scintigraphy and ultrasonography of the neck. The study protocol included measurement of the concentration of calcium, phosphorus, and PTH in the blood serum and performing PET/CT with [11C]MET. Results: A positive result of PET/CT was obtained in 89.5% of the patients (17/19). Parathyroidectomy was performed in 52.9% of the patients (9/17) with positive results of PET/CT with [11C]MET, which were fully consistent with the results of the histopathological examinations of the removed parathyroid glands. On this basis, the sensitivity of PET/CT with [11C]MET in the preoperative localization diagnosis of patients with tHP was found to be 100%. Multiple lesions were visualized in 57.9% of the patients (11/19). Ectopic lesions were visualized in 21.1% of the patients (4/19). Conclusions: PET/CT with [11C]MET is a sensitive technique for the second-line preoperative imaging of parathyroid glands in patients with tertiary hyperparathyroidism in whom first-line examinations, such as ultrasound and scintigraphy, has failed.

Parathyroid Surgery: What Radiologists Need to Know.

Surgical intervention remains the mainstay of treatment of hyperparathyroidism and provides the highest chance at cure. After the disease is confirmed by biochemical testing, surgeons must use a combination of patient clinical history and radiographic imaging to determine the most appropriate surgical strategy. Through either minimally invasive parathyroidectomy or bilateral cervical exploration, surgeons provide high rates of cure for hyperparathyroidism with low rates of persistence or recurrence.

18F-FDG PET/CT in the Hyperparathyroidism-Jaw-Tumor Syndrome.

ABSTRACT: Hyperparathyroidism-jaw-tumor syndrome (HPT-JTS) is a rare autosomal dominant disorder. A typical manifestation of HPT-JTS is the association of jaw-ossifying fibroma with primary hyperparathyroidism. Due to its rarity and diversity in its manifestations, it is a challenging diagnosis. A 33-year-old woman was referred due to painful swelling of the right maxilla suggestive of malignancy. The clinical presentations were not conclusive until she underwent F18-fluorodeoxyglucose positron emission tomography/computed tomography (F18-FDG PET/CT). F18-FDG PET/CT proved to be a useful tool to assist the clinicians in visualizing the "bigger picture" and, therefore all manifestation as pieces of "one puzzle."

Preoperative Imaging in Renal Transplant Patients with Tertiary Hyperparathyroidism.

BACKGROUND: Tertiary hyperparathyroidism following kidney transplantation is most commonly characterized by 4-gland hyperplasia, but single and double adenomatous disease has been demonstrated in this population as well. It is unknown whether preoperative imaging can assist in identifying patients who may qualify for focused surgery for adenomatous disease. MATERIALS AND METHODS: We performed a retrospective review of our patient database from 1998-2018 for patients with tertiary hyperparathyroidism following renal transplant. Patient charts were reviewed for patient demographics, laboratory values, preoperative imaging, operative findings, pathology, and complications. RESULTS: We identified 113 patients with tertiary hyperparathyroidism following renal transplant who underwent parathyroidectomy. There were 51 females and 62 males with a mean age of 53.4 ± 13.4 years. Median preoperative calcium and PTH were 10.9 mg/dl (IQR 10.3-11.2) and 228 pg/ml (IQR 118-305). Preoperative ultrasound was performed in 60 patients. Of these, 11 (18%) were negative, 38 (63%) showed 1-2 adenomas, and 11 (18%) showed ≥ 3 adenomas. 99mTc-sestamibi parathyroid scintigraphy was performed in 101/113 patients. Of these, 11 (11%) were negative, 62 (61%) showed 1-2 areas of discordant sestamibi uptake, and 28 (28%) showed ≥ 3 areas of discordant uptake. Ultimately, 19 (17%) patients had a single adenoma removed, 16 (14%) had 2 adenomas removed, and (69%) had multi-gland disease. There were 26 ectopic glands found in 21 patients, 42.3% of which were identified on preoperative imaging. 94.1% of patients were eucalcemic at last follow-up, mean (± SD) 5.8 ± 3.6 years. Adenomas that were visualized on ultrasound were larger on pathology than those non-visualized (997 ± 120 mg (mean ± SE) vs. 388 ± 109 mg, p = 0.0003). This was also true for parathyroid scintigraphy (647 ± 41 mg vs. 355 ± 51 mg, p = 0.0001). CONCLUSION: In patients with tertiary hyperparathyroidism, preoperative imaging can aid in predicting which patients will have 1-2 gland disease. In patients with 1-2 gland disease on congruent ultrasound and nuclear medicine imaging studies, the accuracy increases to 59%. Preoperative imaging can help identify ectopic glands. Larger adenomas are more likely to be identified on both imaging modalities.

Incidental Detection of a Small Cell Lung Cancer by 18F-Choline PET/CT Performed for Recurrent Hyperparathyroidism After Parathyroidectomy.

ABSTRACT: We report the case of a 64-year-old woman with musculoskeletal pain and elevated serum parathyroid hormone who had undergone parathyroidectomy for primary hyperparathyroidism 4 years earlier. An 18F-choline PET/CT scan was performed and incidentally showed an intense uptake in a right upper lobe pulmonary nodule and in the right hilar, mediastinal, and cervical lymph nodes. Histopathological analysis confirmed the diagnosis of a small cell lung cancer. Clinical symptoms and recurrent hyperparathyroidism were therefore consistent with a paraneoplastic syndrome. A complete metabolic response was achieved on 18F-FDG PET/CT scan after chemotherapy.