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Neuroendocrine tumors (NETs) are a rare spectrum of neoplasms that are characterized by neuroendocrine and neural differentiation. The treatment can be challenging in view of the heterogeneity in differentiation and behavior. Primary renal origin NETs are rare and only a few cases have been reported in the literature. There is limited knowledge on their presentation and response to various lines of treatment. We report a case of a patient with a metastatic renal NET from a rare histological subtype of large cell neuroendocrine carcinoma, known to cause aggressive disease with poor prognosis. A multimodality treatment approach was followed. In spite of surgical management and second-line chemotherapy, the disease progressed. The patient subsequently received peptide receptor radionuclide therapy (PRRNT) using lutetium-177 DOTATATE, following which the patient demonstrated a remarkable clinical and radiological response and is stable to date. In a rare tumor with poor prognosis, the relevance of theranostics and the efficacy of targeted therapies like PRRNT are noteworthy., Competing Interests: Conflict of Interest None declared., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. ( https://creativecommons.org/licenses/by/4.0/ ).)

Background  Pulmonary metastases in papillary thyroid carcinoma have two common presentations-micro/miliary (MM) and macronodular metastases (MN). The mainstay of treatment, posttotal thyroidectomy, is multiple radioactive iodine ablations (RAIA) every 6 to 12 months. Response assessment is determined by decline in stimulated serum thyroglobulin levels (sTg), disease regression on chest x-ray (CXR), computed tomography thorax, or whole body iodine scintigraphy (TWBS). Aim  This study aims to assess the difference in response to RAIA based on the pattern of presentation. Methodology  Retrospective analysis of patients from January 2008 to July 2017 was done. Patients with pulmonary metastases treated with RAIA (3700MBq per therapy as opposed to theAmerican Thyroid Association recommendation of 7400MBq per therapy) and a minimum follow-up of 8 months were included. The initial and the final sTg, TWBS, and CXR were analyzed for both groups. Final outcome in terms of complete response, disease regression, static disease, and disease progression was determined. Results  Of the total of 1,793 patients, 71 were included. There were 43 females and 28 males. The median age was 39 years and the range was 14 to 79 years. Forty-five (63.3%) patients had MM and 26 (36.6%) patients had MN disease. The average number of therapies was three and maximum follow-up period was 15 years. Of the 45 MM patients, 1 had progression, 7 were static, 23 had regression, and 14 had complete response. Of the 26 MN patients, 22 had progression, 2 were static, 1 had regression, and 1 had complete response. Conclusion  MM metastases, when compared with MN disease, respond to RAIA with a better outcome. In addition to achieving comparable response with a lower dose per therapy, there were no radiation-related long-term complications reported., Competing Interests: Conflict of Interest None declared., (World Association of Radiopharmaceutical and Molecular Therapy (WARMTH). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. ( https://creativecommons.org/licenses/by-nc-nd/4.0/ ).)

Positron emission tomography-computed tomography (PET-CT) has been used as an imaging modality in workup of fever of unknown origin (FUO). The aim of our study is to evaluate the diagnostic utility of PET-CT in FUO workup in a resource-limited setting. We also looked at laboratory parameters as predictors of contributory PET-CT scans and propose an algorithm for evaluation of FUO in resource-limited tropical regions. This retrospective observational study included patients admitted for FUO workup under general medicine in a teaching hospital in South India from June 2013 to May 2016. PET-CT was done when the patient remained undiagnosed after a detailed clinical assessment and first- and second-tier investigations. Among 43 patients included in our study, a definite diagnosis was established in 74% (32). Noninfectious inflammatory diseases, infections, malignancies, and miscellaneous diseases were diagnosed in 37.2% (16/43), 23.3% (10/43), 9.3% (4/43), and 4.7% (2/43), respectively. Tuberculosis was the single most common disease seen in 20.9% (9/43). PET-CT scans were contributory toward establishment of final diagnosis in 90.7% (39/43). High C-reactive protein (CRP) and aspartate aminotransferase (AST) levels were associated with contributory PET-CT scans ( P = 0.006 and 0.011, respectively). PET-CT delineating organ/tissue for diagnostic biopsy was associated with final diagnosis of infectious disease ( P = 0.001). Sensitivity, specificity, and positive and negative predictive value of PET-CT scans were 76.9% (20/26), 33.3% (2/6), 83% (20/24), and 25% (2/8), respectively. High CRP and AST were predictors of contributory PET-CT scans. PET-CT scans have high sensitivity and positive predictive value when used in evaluation of FUO. Although it is a useful tool in FUO workup, especially in the diagnosis of tropical infections, PET-CT should be done after a comprehensive clinical assessment and basic investigations., Competing Interests: There are no conflicts of interest., (Copyright: © 2021 World Journal of Nuclear Medicine.)

In low-risk differentiated thyroid carcinoma (LRDTC), appropriate surgical procedure in terms of hemi/total thyroidectomy (TT) has been an area of debate. The aim was to determine whether in LRDTC patients, hemithyroidectomy would be an adequate treatment, determine incidence of disease in contralateral lobe and evaluate the effect of radioactive iodine ablation (RAIA). Retrospective study was done from 2008 to 2014 at a single institution. Preoperative ultrasound (USG) and histopathology reports of all LRDTC patients following total/completion thyroidectomy were recorded. Details of postthyroidectomy, thyroid whole body scan, and stimulated serum thyroglobulin (sTg) levels were also documented and results analyzed. A total of 114/562 patients met inclusion criteria. Of these, 25/114 (22%) underwent hemithyroidectomy followed by a completion thyroidectomy while remaining 89/114 (78%) underwent TT initially. Preoperative USG detected single-lobe involvement in 44 patients; however, among them, histopathology revealed bilateral lobe disease in 17 (38.6%). There was a significant fall of sTg level following RAIA as compared to that before RAIA in T1b-T2 ( P = 0.009 and 0.012, respectively). Median follow-up was 2 years (range: 1-7 years) with no distant metastasis or deaths recorded till 2017, except for one local recurrence 4 years after RAIA. In conclusion, the role of TT in LRDTC patients is important as 46% of patients were found to have tumor in contralateral lobe as well. Significant fall in sTg levels following RAIA justifies RAIA of remnant lobe even in LRDTC (T > 1a). It facilitates early detection of recurrence when sTg alone is used for follow-up., Competing Interests: There are no conflicts of interest.

Serum thyroglobulin (Tg) and thyroid whole-body radioiodine scintigraphy (TWBS) are used in the follow-up of patients with papillary thyroid carcinoma (PTC) after total thyroidectomy. Symptoms of hypothyroidism are frequent as patients discontinue levothyroxine 1 month before visit, favoring the use of unstimulated serum Tg (uSTg) only. This study was done to determine the reliability of stimulated serum Tg levels (sSTg) over uSTg. A total of 650 patients with PTC came for follow-up between June 2011 and 2016. In those who had levels of uSTg and sSTg months measured within an interval of median of 3 months (range from 1 to 8 months), risk stratification was done as per the American Thyroid Association guidelines 2015. Intervention was based on a cutoff value of sSTg >10 ng/ml in our institution and the same was used for data analysis. Out of 650 patients, 106 had paired Tg values. Low-, intermediate-, and high-risk groups comprised 40, 31, and 35 patients, respectively. The sSTg >10 ng/ml with uSTg <10 ng/ml in the same patient was noted in 22.5% (9/40) of the low-risk, 41.9% (13/31) of the intermediate-risk, and 14.2% (5/35) of the high-risk groups. The levels were corroborated with tumor burden as determined by additional clinical, ultrasonography neck, and TWBS findings. Our study highlights the superiority of sSTg over uSTg in the follow-up of PTC patients. Follow-up with uSTg alone may result in underestimating the tumor burden., Competing Interests: There are no conflicts of interest.