FDG PET/CT Image for a Rosai-Dorfman Disease With Pituitary and Bone Involvement in a Pediatric Patient Rosai-Dorfman disease, also known as sinus histiocytosis with massive lymphadenopathy, is a rare nonneoplastic histiocytic disorder that often involves the lymph nodes and occasionally the central nervous system or skeleton. However, the presence of extranodal Rosai-Dorfman lesions without lymphadenopathy is extremely rare. Here we present a case of a pathological confirmed Rosai-Dorfman disease with pituitary and skeletal involvement without lymph nodes involvement. Received for publication March 2, 2019; revision accepted July 13, 2019. Conflicts of interest and sources of funding: This study was funded by the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (grant no. 2016-I2M-2-001 and no. 2018-I2M-3-001) and the Fundamental Research Funds for the Central Universities (Grant No. 3332018029). None declared to all authors. Correspondence to: Xin Cheng, MD, Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No.1 Shuaifuyuan, Wangfujing, Dongcheng District, Beijing, China. E-mail: pumch_chengxin@126.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

18F-FDG PET/CT Findings of Ovarian Mesothelioma: A Case Study Ovarian mesothelioma is a rare and aggressive tumor. Early diagnosis of the disease is difficult, delaying effective treatment. Here we report a 50-year-old woman who was referred for an 18F-FDG PET/CT imaging to assess her newly detected left ovarian mass. The images not only demonstrated a hypermetabolic mass in the left ovary, but also several hepatic low densities with increased FDG uptake, which suggested ovarian malignancy with hepatic metastases. Mesothelioma was diagnosed histopathologically following the biopsy. Our case demonstrates PET/CT findings observed in ovarian mesothelioma. Received for publication May 26, 2019; revision accepted July 23, 2019. Conflicts of interest and sources of funding: none declared. Correspondence to: Zhanwen Huang, MD, Department of Nuclear Medicine, the Affiliated Hospital, Southwest Medical University, No. 15 TaiPing St, Jiangyang District, Luzhou, Sichuan, People's Republic of China 646000. E-mail: huangzhanwen1573@163.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

In Vivo Assessment of Tau Deposition in Alzheimer Disease and Assessing Its Relationship to Regional Brain Glucose Metabolism and Cognition Aim In this study, we investigated the relationship of cerebral tau deposition (18F-tau-AD-ML 104 PET/CT) with glucose metabolism (18F-FDG PET/CT) and cognitive function in patients with Alzheimer disease (AD). Patients and Methods Seventy subjects (Mini Mental State Examination [MMSE] score <18 = 37 [AD]; MMSE score, 18–24 = 16 [early AD]) and 17 controls were included in this study. All participants underwent detailed neurological and neuropsychological evaluation, followed by 18F-tau-AD-ML 104 and 18F-FDG PET/CT imaging. Region-wise SUVmax ratios at 50 to 60 minutes postinjection were calculated for 18F-tau-AD-ML 104 and 18F-FDG, using the cerebellar cortex as the reference region. Linear models were used to investigate the association of regional 18F-tau-AD-ML 104 retention with 18F-FDG uptake and cognition (MMSE scores). Results 18F-Tau-AD-ML 104 retention was observed in the parietal lobe, temporal lobe, hippocampus, parahippocampus, frontal lobe, anterior and posterior cingulate, and precuneus in advanced and early AD patient as compared with normal controls with regional hypometabolism in overlapping regions on 18F-FDG PET. Significant negative association was found between 18F-tau-AD-ML 104 regional retention and glucose metabolism in the parietal lobe, temporal lobe, hippocampus, parahippocampus, frontal lobe, anterior and posterior cingulate, and precuneus among patients with advanced and early AD. In advanced and early AD patients, a negative association was found between 18F-tau-AD-ML 104 regional retention (precuneus) and cognition (MMSE score), whereas a positive association was observed between 18F-FDG regional uptake (precuneus) and cognition (MMSE score). Conclusions Tau pathology overlapped with areas of hypometabolism on FDG PET in the brains of AD patients. Tau deposition was found to have negative association with cognitive scores in these patients. Received for publication May 1, 2019; revision accepted July 22, 2019. Conflicts of interest and sources of funding: none declared. Correspondence to: Madhavi Tripathi, MD, DNB, Department of Nuclear Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India. E-mail: madhavi.dave.97@gmail.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Identification of Distant Metastases From Recurrent Gliosarcoma Using Whole-Body 18F-FDG PET/CT A 51-year-old man presented with recurrent gliosarcoma and increasing cough over the last months. On 18F-FDG PET/CT, solid lung masses with high 18F-FDG uptake were present. A biopsy taken from a lung lesion indicated distant metastases from gliosarcoma. Gliosarcoma, a rare malignant central nervous system tumor, presents with extracranial metastases in only less than 10%. As highlighted by this case, 18F-FDG PET/CT can be used for whole-body staging in patients with metastatic brain tumor. Vice versa, highly 18F-FDG–avid lung lesions in patients with brain tumors should lead to distant metastases as differential diagnosis despite their rare occurrence. Received for publication May 23, 2019; revision accepted July 22, 2019. Conflicts of interest and sources of funding: none declared. Authors' Contributions: M.U. and N.L.A.: drafting of the manuscript, PET/CT reading, and conceiving the design. V.R., J.H., and U.S.: neuropathological evaluation, increased intellectual content, and revision of the manuscript. C.C.C.: PET/CT and MRI reading, increased intellectual content, and revision of the manuscript. M.B.: PET/CT reading, increased intellectual content, and revision of the manuscript. N.T., J.C.T., and P.B.: clinical management, increased intellectual content, and revision of the manuscript. Correspondence to: Marcus Unterrainer, MD, MSc, Department of Nuclear Medicine, LMU, Marchioninistr. 15, 81377 Munich, Germany. E-mail: marcus.unterrainer@med.uni-muenchen.de. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

A Novel Application of [18F]Fluorothymidine-PET ([18F]FLT-PET) in Clinical Practice to Quantify Regional Bone Marrow Function in a Patient With Treatment-Induced Cytopenias and to Guide “Marrow-Sparing” Radiotherapy 18F-Fluorothymidine-positron emission tomography with CT fusion ([18F]FLT-PET/CT) offers a unique and non-invasive method for three-dimensional localization and quantification of functional bone marrow. [18F]FLT-PET/CT has potential application in radiotherapy planning when risk of marrow toxicity is a significant clinical concern. In this patient with chemo-refractory, transformed lymphoma and treatment-induced cytopenias, [18F]FLT-PET/CT was a novel and useful adjunct to (1) image the distribution of functional bone marrow reserve, (2) guide “marrow-sparing” radiotherapy planning, and (3) quantify the effects of radiotherapy-induced bone marrow suppression both in-field and out-of-field. Received for publication March 24, 2019; revision accepted July 21, 2019. Conflicts of interest and sources of funding: none declared. Correspondence to: Belinda A. Campbell, Peter MacCallum Cancer Centre, Locked Bag 5, A’Beckett St, Melbourne, Victoria 8006, Australia. E-mail: belinda.campbell@petermac.org. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Polyarteritis Nodosa With Reversible FDG Accumulation in Vessels and Kidneys A 59-year-old man presented with fever and lower extremity myalgia. Laboratory studies revealed elevated C-reactive protein. 18F-FDG PET/CT demonstrated FDG uptake not only in the brachial arteries, femoral arteries, and their main ramifications, which were equivalent to small- to medium-sized arteries but also in the kidneys. Angiography revealed a renal aneurysm, confirming the diagnosis of polyarteritis nodosa. The increased FDG uptake in the vessels and kidneys resolved after 6 months of glucocorticoid treatment. Received for publication March 26, 2019; revision accepted July 21, 2019. Conflicts of interest and sources of funding: This study was supported by a grant from the National Center for Global Health and Medicine (no. 29-2005). None declared to all authors. Correspondence to: Hiroyuki Yamashita, MD, PhD, Division of Rheumatic Diseases, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo 162-8655 Japan. E-mail: hiroyuki_yjp2005@yahoo.co.jp. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Excellent Response to 177Lu-DOTATATE Peptide Receptor Radionuclide Therapy in a Patient With Progressive Metastatic Castration-Resistant Prostate Cancer With Neuroendocrine Differentiation After 177Lu-PSMA Therapy Prostate cancer with neuroendocrine differentiation is associated with a poor prognosis, rapid disease progression, and treatment resistance, and constitutes a diagnostic and therapeutic dilemma. We present images of 177Lu-DOTATATE scan and 68Ga-DOTATATE PET/CT scan conducted on a 65-year-old man with prostate cancer with neuroendocrine differentiation, whose disease progressed despite conventional treatment and 177Lu-PSMA radioligand therapy; however, an extraordinary radiographic tumor remission, biochemical response, and improvement of clinical symptoms were observed after the patient underwent 177Lu-DOTATATE peptide receptor radionuclide therapy. Received for publication March 7, 2019; revision accepted July 18, 2019. C.L. and T.L. contributed equally to this work. Conflicts of interest and sources of funding: Chen Liu was supported by grants from Interdisciplinary Medicine Seed Fund of Peking University (BMU2017MX007). None declared to the other authors. Correspondence to: Zhi Yang, PhD, Department of Nuclear Medicine, Beijing Cancer Hospital, No. 52 Fucheng Rd, Beijing, 100142, China. E-mail: pekyz@163.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

18F-FDG PET/CT of Multiorgan Sarcoid-Like Reaction During Anti–PD-1 Treatment for Melanoma We report a case of a 50-year-old woman treated with anti–PD-1 inhibition for metastatic melanoma. During treatment, extensive and transient histopathologically confirmed sarcoid-like reaction was detected in multiple organ systems and at different time points using 18F-FDG PET/CT imaging. Immune-related adverse events during anti-PD-1/PD-L1 antibody treatment are increasingly being reported. This case report emphasizes the broad spectrum of possible presentations of sarcoid-like reaction detected by 18F-FDG PET/CT and its evolution in time. For the clinician, awareness of these immune-related adverse events helps to accurately interpret findings on imaging. Received for publication April 18, 2019; revision accepted July 13, 2019. Conflicts of interest: W.R.G. received speaker's fees from Bayer and MSD; W.R.G. received consultancy fees for participation in advisory boards of Bristol-Myers Squibb, Astellas, Bayer, Sanofi, and Amgen; W.R.G. received research grants from Bayer and Astellas. All other authors (W.v.W. and E.A.) declare to have no conflict of interest. Correspondence to: Erik H.J.G. Aarntzen, MD, PhD, Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, the Netherlands. E-mail: erik.aarntzen@radboudumc.nl. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Spectrum of 18F-FDG Uptake in Bilateral Lung Parenchymal Diseases on PET/CT Bilateral lung parenchymal involvement is seen in infective as well as noninfective conditions, appearing as focal or diffuse lung disease. PET/CT with FDG helps in characterization (increased glucose utilization is seen by both inflammatory and neoplastic cells). In this article, we describe the spectrum of patterns of FDG uptake and associated CT changes involving bilateral lung parenchyma. Benign conditions described are aspiration pneumonia; pulmonary toxicity by bleomycin; infections, namely, sarcoidosis, miliary pulmonary tuberculosis, and pulmonary nocardiosis; and inflammatory conditions such as pulmonary Langerhans cell histiocytosis and pulmonary alveolar proteinosis. Neoplastic conditions described are bilateral pulmonary metastases and lymphangitic carcinomatosis. Received for publication March 11, 2019; revision accepted July 1, 2019. Conflicts of interest and sources of funding: none declared. Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent: The institutional review board of our institute approved this retrospective study, and the requirement to obtain informed consent was waived. Correspondence to: Rakesh Kumar, MD, PhD, Department of Nuclear Medicine, AIIMS Campus, E-81, Ansari Nagar (East), New Delhi 110029, India. E-mail: rkphulia@yahoo.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Pituitary Adenoma on 18F-Fluciclovine PET/CT A 69-year-old man presented with lower urinary tract symptoms and prostate biopsy showed prostate cancer. 18F-Fluciclovine PET/CT revealed abnormal increased radiotracer uptake within the prostate gland, and multiple osseous structures, suspicious for tumoral involvement. Incidentally, an expansile soft tissue density mass arising from sella turcica demonstrated increased radiotracer activity. MRI showed a lobulated enhancing mass centered in the sella and eroding into the sphenoid sinus. The differential diagnosis includes pituitary macroadenoma versus prostate cancer metastasis. The tumor was resected and the pathological diagnosis was pituitary adenoma. Received for publication May 3, 2019; revision accepted July 13, 2019. Conflicts of interest and sources of funding: none declared. Correspondence to: Jiaqiong Wang, MD, PhD, Division of Nuclear Medicine, Department of Radiology, Miller School of Medicine, University of Miami Hospital/Jackson Memorial Hospital. Nuclear Medicine, Central 248 JMH, 1611 NW 12th Avenue, Miami, FL 33136, USA. E-mail: jiaqiong.wang@jhsmiami.org. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.