Nishikant Damle

PSMA Expression in Papillary Thyroid Carcinoma: Opening a New Horizon in Management of Thyroid Cancer?

Prostate-specific membrane antigen (PSMA) is a type 2 transmembrane protein highly expressed in prostate cancer cells. We present the case of a 50-year-old man with metastatic papillary carcinoma of the thyroid, with rising thyroglobulin level and negative whole-body radioiodine scan after total thyroidectomy. Considering the limited treatment options available, it was decided to perform Ga-PSMA-HBED-CC PET/CT scan. It revealed intense radiotracer uptake in mediastinal and left supraclavicular lymph nodes, brain metastases, bilateral lung nodules, and skeletal sites. Patient also underwent F-FDG PET/CT. It demonstrated similar findings; however, the number of lesions detected in brain was less compared with Ga-PSMA PET/CT.

Differential Diagnosis of Neurodegenerative Dementias Using Metabolic Phenotypes on F-18 FDG PET/CT:

Positron emission tomography (PET) imaging with F-18 fluorodeoxyglucose (FDG) can be used as a downstream marker of neuronal injury, a hallmark of neurodegenerative dementias. Characteristic patterns of regional glucose metabolism have been used to classify the dementia subtypes, namely Alzheimers dementia (AD), frontotemporal dementia (FTD), diffuse Lewy body (DLBD) and vascular dementia (VD). We undertook this study to assess the utility of FDG-PET in the differential diagnosis of dementia subtypes. One hundred and twenty-five patients diagnosed with dementia were referred from cognitive disorders and memory clinics of speciality neurology centres for the FDG-PET study. Imaging-based diagnosis of dementia type was established in 101 patients by visual assessment of individual scans by a PET physician blinded to the clinical diagnosis. The results were compared with an 18-month follow-up clinical assessment made by the specialist neurologist. Concordance of visual evaluation of FDG-PET scans with clinical diagnosis of the dementia type was achieved in 90% of patients scanned. This concordance was 93.4% for AD, 88.8% for FTD, 66.6% for DLBD and 92.3% for the other dementia syndromes. FDG-PET performed after the initial work-up of dementias is useful for supporting the clinical diagnosis of dementia subtype.

A curious case of refractory hypothyroidism due to selective malabsorption of oral thyroxine.

There are very few cases in the literature in which refractory persistent hypothyroidism responded only to parenteral doses of levothyroxine and no evidence of any malabsorptive disorder could be identified. Here, we present a rare case of a 35-year-old woman with refractory hypothyroidism who responded only to intravenous doses of levothyroxine. We also discuss possible causes for the same.

Diagnosis of Men-I Syndrome on 68Ga-DOTANOC PET-CT and Role of Peptide Receptor Radionuclide Therapy With 177Lu-DOTATATE

Abstract MEN-I is a rare genetic disorder classically characterized by a predisposition to tumors of the parathyroid glands, anterior pituitary gland, and pancreatic islet cells. We present a case of MEN-I syndrome diagnosed using predominantly nuclear medicine imaging followed by radionuclide therapy, thus emphasizing the role of nuclear imaging in diagnosing and treating MEN-I.

Papillary carcinoma masquerading as clinically toxic adenoma in very young children.

Abstract Background: Autonomously functioning thyroid nodules (AFTN) are extremely rare in children. Malignancy may be rarely found in hyperfunctioning ‘hot’ nodules in adults. However, there are limited reports of AFTNs in young children presenting as or developing malignancy in future. We report here two young children aged <6 years old at the time of diagnosis as having an AFTN, which eventually turned out to be papillary carcinoma of thyroid (PTC) on follow-up. Patient findings: A 2-month-old baby had a right-sided neck swelling since birth. On examination, the baby had clinical and biochemical features of thyrotoxicosis. On sonography, and subsequently on 99mTc-pertechnetate thyroid scan, a hot nodule was found. Patient was treated with carbimazole for 5 years. In spite of euthyroidism achieved, the nodule continuously grew in size. Thyroid cytology was inconclusive, hence hemithyroidectomy was performed and histopathology turned out to be PTC. Another 5-year-old female child had a large right-sided AFTN on thyroid scan. She was treated with radioiodine; however, like the previous case, the nodule started growing in size. She subsequently underwent near total thyroidectomy and histology was reported as PTC. Conclusion: In the light of this report that shows that solitary hyperfunctioning nodules in very young children have high chance of malignancy, we recommend hemithyroidectomy as the treatment of choice.

Comparison of 18F-Fluorocholine positron emission tomography/computed tomography and four-dimensional computed tomography in the preoperative localization of parathyroid adenomas-initial results

Objective: We aimed to compare the diagnostic accuracy of 18F-Fluorocholine (FCH)-positron emission tomography/computed tomography (PET/CT) and four-dimensional (4D)- CT in detection and localization of eutopic and ectopic parathyroid adenoma (PA) in patients with hyperparathyroidism. Materials and Methods: Five patients with primary hyperparathyroidism underwent FCH-PET/CT after 60 min of 185 MBq of intravenous 18F-FCH administration. Images were acquired from head to mediastinum at 3 min per bed position. No intravenous contrast was used. All patients underwent 4D-CT within 2 weeks of the FCH-PET/CT, with a precontrast, post contrast arterial, and venous phase with 75 ml intravenous Iohexol 350 followed by 25 ml saline chase. Histopathology was considered as the gold standard. Results: Both modalities showed 100% concordance in the detection of parathyroid lesions. Both FCH-PET/CT and 4D-CT detected 7 lesions in 5 patients, with 4 patients having a single lesion, and 1 patient having three lesions. Of the 7 reported lesions, 4 were eutopic and 3 were ectopic. No additional lesions were detected by either modality in comparison to the other. All 7 specimens were resected and histopathology showed PA/hyperplasia. Conclusion: FCH-PET/CT and 4D-CT are equally efficacious in detection and localization of eutopic and ectopic PA. This may open up the possibility of using FCH-PET/CT in patients with negative conventional imaging who cannot undergo contrast studies.

Role of 99m Tc-MDP bone scan in the diagnosis of Erdheim-Chester disease

Erdheim–Chester disease (ECD) is a rare systemic non-Langerhans cell histiocytosis. It is a progressive disease of unknown etiology. The 99mtechnetium-methylene diphosphonate (99mTc-MDP) bone scan is useful in finding the sites of involvement in the skeleton and is helpful in excluding other causes of bony pain. Also a scintigraphic pattern consistent with ECD should alert the physician to evaluate the patient for visceral sites of involvement using fludeoxyglucose positron emission tomography/computed tomography (FDG PET/CT), as this is known to be fatal at times.

Discordance in 68Ga-DOTANOC and 177Lu-DOTATATE uptake in diagnostic and post-therapy scans in patients with medullary thyroid cancer-likely reasons

Sir, We qualitatively studied the discordance between pre-therapy 68Ga-DOTANOC scans and post-therapy 177Lu-DOTATATE scans in patients with medullary thyroid cancer (MTC). Patients with metastatic/recurrent, inoperable MTC showing good uptake of Ga-DOTANOC on positron emission tomography (PET)/computed tomography (CT); >18 years of age with serum creatinine ≤1.3 mg%, bilirubin ≤1 mg%, SGOT, SGPT ≤50 IU; baseline normalized GFR (2 sample method-Tc-DTPA) ≥70 ml/min/1.73 mr, Hb ≥9 gms%, TLC ≥4000/μl, platelets ≥1,50,000/μl were included in this study.

Retinoic acid therapy in patients with radioiodine negative differentiated thyroid cancer and clinical or biochemical evidence of disease: An initial experience.

Background: Dedifferentiation of thyroid follicular cells renders radioiodine therapy ineffective in patients of differentiated thyroid cancer (DTC). An alternative therapy to treat the disease or reinduce radioiodine uptake is necessary. Materials and Methods: We evaluated the role of retinoic acid therapy in 13 cases of DTC with raised thyroglobulin and/or clinically evident disease. Retinoic acid was given in a dose of 1.5 mg/kg for a period ranging between 1.5 and 18 months. Results: Age of the patients was between 18 and 65 years with a median of 49 years. Ten patients had papillary while two had follicular and one patient had mixed papillary and follicular thyroid cancer. Mean radioiodine given before starting retinoic acid was 164 mCi. Mean duration of therapy was 6.4 months. Thyroglobulin decreased in 2 patients and increased in 11 patients at the end of therapy. Radioiodine uptake was demonstrable in six patients, though faintly, while 7 cases showed no uptake. Based on the clinical and biochemical parameters, four patients had progressive disease, eight had stable disease and one patient showed partial response. Of the six patients with reinduction of radioiodine uptake, three had biochemical progression and the other three had stable disease. Conclusion: Our findings suggest that retinoic acid therapy may induce radioiodine uptake and reduce serum thyroglobulin levels in some patients with DTC, but whether this results in clinically significant response can only be ascertained on long-term follow-up.

Incidental detection of hyperfunctioning thyroid cancer metastases in patients presenting with thyrotoxicosis.

Thyrotoxicosis due to functioning metastases from thyroid cancer is rare. It also presents a therapeutic challenge, as both the metastatic cancer and thyrotoxicosis need to be treated. We present here two cases of thyrotoxicosis which on a routine 99mTc-pertechnetate thyroid scan showed extrathyroidal foci of uptake. Two patients who initially presented with thyrotoxicosis underwent a routine thyroid scan. Abnormal uptake in the shoulder was incidentally noted, which prompted us to do a whole body pertechnetate scan in the same sitting, which revealed extensive hyperfunctioning metastases in the lungs and bones. We also discuss the ‘Flip Flop’ phenomenon in thyroid cancer, which was seen in our case. This report emphasizes the importance of evaluating the abnormal foci of uptake seen on a routine thyroid scan.