Clinical Nuclear Medicine

Solitary Vulvar Involvement of Ovarian Non-Hodgkin Lymphoma Mimicking Bartholin's Abscess on 18F-FDG PET/CT A 49-year-old woman was diagnosed with diffuse large B-cell lymphoma of the left ovary. Two months after the hysterectomy and bilateral salpingo-oophorectomy operation, the patient was referred to 18F-FDG PET/CT for staging. A mass lesion measuring 2.8 × 3 cm with intense 18F-FDG uptake was observed at right labium majus, which could be considered as a Bartholin's cyst or abscess. The lesion was excised, and non-Hodgkin lymphoma involvement of vulva was revealed by histopathology. Received for publication October 2, 2020; revision accepted November 15, 2020. Conflicts of interest and sources of funding: none declared. Correspondence to: Nurhan Ergül, MD, Clinic of Nuclear Medicine, Istanbul Training and Research Hospital, Kasap İlyas Mah. Org. Abdurrahman Nafiz Gürman Cd. 34098 Fatih, Istanbul, Turkey. E-mail: nurhanergul@yahoo.com. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.

Prospective Correlation of Prognostic Immunohistochemical Markers With SUV and ADC Derived From Dedicated Hybrid Breast 18F-FDG PET/MRI in Women With Newly Diagnosed Breast Cancer Purpose The aim of this study was to correlate prognostically relevant immunohistochemical parameters of breast cancer with simultaneously acquired SUVs and apparent diffusion coefficient (ADC) values derived from hybrid breast PET/MRI. Patients and Methods Fifty-six women with newly diagnosed, therapy-naive, histologically proven breast cancer (mean age, 54.1 ± 12.0 years) underwent dedicated prone 18F-FDG breast PET/MRI. Diffusion-weighted imaging (b-values: 0, 500, 1000 s/mm2) was performed simultaneously with the PET acquisition. A region of interest encompassing the entire primary tumor on each patient's PET/MRI scan was used to determine the glucose metabolism represented by maximum and mean SUV as well as into corresponding ADC maps to assess tumor cellularity represented by mean and minimum ADC values. Histopathological tumor grading and prognostically relevant immunohistochemical markers, that is, Ki67, progesterone receptor, estrogen receptor, and human epidermal growth factor receptor 2 (HER2), were assessed. Pearson correlation coefficients were calculated to compare SUV and ADC values as well as the immunohistochemically markers and molecular subtype. For the comparison with the tumor grading, a Wilcoxon test was used. Results A significant inverse correlation between SUV and ADC values derived from breast PET/MRI (r = −0.49 for SUVmean vs ADCmean; r = −0.43 for SUVmax vs ADCmin; both P's < 0.001) was found. Tumor grading and Ki67 both showed a positive correlation with SUVmean from breast PET/MRI (r = 0.37 and r = 0.32, P < 0.01). For immunohistochemical markers, HER2 showed an inverse correlation with ADC values from breast PET/MRI (r = −0.35, P < 0.01). Molecular subtypes significantly correlate with SUVmax and SUVmean (r = 0.52 and r = 0.42, both P's < 0.05). In addition, estrogen receptor expression showed an inverse correlation with SUVmax and SUVmean from breast PET/MRI (r = −0.45 and r = −0.42, P < 0.001). Conclusions The present data show a correlation between increased glucose metabolism, cellularity, tumor grading, estrogen and HER2 expression, as well as molecular subtype of breast cancer primaries. Hence, simultaneous 18F-FDG PET and diffusion-weighted imaging from hybrid breast PET/MRI may serve as a predictive tool for identifying high-risk breast cancer patients in initial staging and guide-targeted therapy. Received for publication August 23, 2020; revision accepted November 12, 2020. J.M. and J.K. contributed equally to this study. Conflicts of interest and sources of funding: The authors declare no conflict of interest. The study is funded by Deutsche Forschungsgemeinschaft, a German research foundation (BU3075/2-1). The funding foundation was not involved in the trial design, patient recruitment, data collection, analysis, interpretation or presentation, writing or editing of the reports, or the decision to submit for publication. The corresponding author had full access to all data in the study and had all the responsibility for the decision to submit for publication. Ethical approval: All procedures performed were in accordance with the ethical standards of the institutional research committee and with the principles of the 1964 Declaration of Helsinki and its later amendments. Informed consent: Informed consent was obtained from all individual participants included in the study. Correspondence to: Julian Kirchner, MD, Department of Diagnostic and Interventional Radiology, Medical Faculty, University Düsseldorf, Moorenstrasse 5, D-40225 Düsseldorf, Germany. E-mail: Julian.Kirchner@med.uni-duesseldorf.de. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.

Intense Diffuse Uptake of 68Ga-FAPI-04 in the Breasts Found by PET/CT in a Patient With Advanced Nasopharyngeal Carcinoma The physiological uptake of 68Ga-FAPI-04 due to the change of the internal environment is little known. We report the case of a 45-year-old woman who was highly suspected to have advanced nasopharyngeal carcinoma. 18F-FDG and 68Ga-FAPI-04 PET/CT was performed for evaluating the disease. Both PET and CT with different tracers detected the primary nasopharyngeal carcinoma and metastases in right neck lymph nodes, liver, and bones. To our surprise, intense diffuse uptake of 68Ga-FAPI-04 was found in both breasts, which might be due to the hormone stimulation because the patient received 68Ga-FAPi-04 PET/CT just at the period of ovulation. Received for publication October 6, 2020; revision accepted November 12, 2020. Conflicts of interest and sources of funding: none declared. Correspondence to: Hu-bing Wu, MD, PET Center, Nanfang Hospital, Southern Medical University, No. 1838 Guangzhou Avenue North, Guangzhou, Guangdong 510515, China. E-mail: wuhbym@163.com. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.

Fibroblast Activation Protein Inhibitor PET/CT: A Promising Molecular Imaging Tool Purpose Fibroblast activation protein (FAP) is a cell membrane–bound serine peptidase, overexpressed in cancer-associated fibroblasts and activated fibroblasts at wound healing/inflammatory sites. Recently, molecular PET/CT imaging with radiolabeled FAP inhibitor (FAPI) has been evaluated in different diseases. We aimed to assess its potential role based on the available literature. Patients and Methods We conducted a comprehensive review of the available preclinical and clinical data on FAPI PET/CT in an attempt to summarize its current status and potential future role. Based on that, we have discussed the pathophysiology behind FAP-based imaging, followed by a discussion of FAPI radiopharmaceuticals including their synthesis, biodistribution, and dosimetry. Next, we have discussed studies evaluating FAPI PET/CT in different oncological and nononcological pathologies. The potential of FAPI PET/CT in theranostics has also been addressed. Results Based on the early scientific evidence available, including preclinical and clinical studies, FAPI PET/CT seems to be a promising molecular imaging tool, especially in oncology. It can be used for imaging different types of cancers and outperforms 18F-FDG PET/CT in some of these. Its potential as a theranostic tool warrants special attention. Conclusions Fibroblast activation protein inhibitor PET/CT has the potential to emerge as a powerful molecular imaging tool in the future. However, as of yet, the available evidence is limited, warranting further research and trials in this field. Received for publication September 8, 2020; revision accepted November 12, 2020. Conflicts of interest and sources of funding: none declared. Correspondence to: Punit Sharma, MD, FEBNM, FANMB, Department of Nuclear Medicine and PET/CT, Apollo Gleneagles Hospital, 58, Canal Circular Rd, Kolkata 700054, India. E-mail: dr_punitsharma@yahoo.com. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.

68Ga-FAPI PET/CT Versus 68Ga-DOTATATE PET/CT in the Evaluation of a Patient With Neuroendocrine Tumor 68Ga-FAPI (fibroblast activation protein-specific inhibitor) PET/CT was performed in a 56-year-old man with multiple liver masses, which were confirmed grade 2 well-differentiated neuroendocrine tumors with liver Tru-Cut biopsy. With 68Ga-DOTATE PET/CT, primary tumor in the pancreas, multiple metastases in the liver and metastatic portocaval lymph node were detected. In 68Ga-FAPI PET/CT imaging performed for comparison, it was seen that metastatic lesions in the liver were distinguished much better because of low background activity, and the primary tumor and metastatic lymph node were clearly selected. This case suggested that FAPI-bounded radionuclides may be useful in the evaluation and targeted therapy of neuroendocrine tumors. Received for publication September 25, 2020; revision accepted November 12, 2020. Conflicts of interest and sources of funding: none declared. Correspondence to: Cihan Gündoğan, MD, Department of Nuclear Medicine, Gazi Yaşargil Training and Research Hospital, University of Health Sciences, Üçkuyular mevki, 21070, Kayapınar, Diyarbakır, Turkey. E-mail: cihangd@hotmail.com. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.

Inferior Vena Cava Tumor Thrombus From Thyroid Cancer Detected by 68Ga-PSMA-617 PET/CT A 61-year-old woman was diagnosed with progressive metastatic radioactive iodine refractory differentiated thyroid cancer and underwent multitargeted tyrosine kinase inhibitor (TKI) Donafenib therapy. After 12 months of therapy, she developed resistance to TKI. Considering the limited treatment options available, a 68Ga–prostate-specific membrane antigen (PSMA)–617 PET/CT was conducted for potential therapeutic target. 68Ga-PSMA-617 PET/CT showed an intense radiotracer uptake in inferior vena cava, which was subsequently confirmed as tumor thrombus. Thus, this patient is a rare case in which the tumor thrombus from thyroid cancer was discovered in inferior vena cava via 68Ga-PSMA-617 PET/CT. Received for publication October 28, 2020; revision accepted November 13, 2020. Conflicts of interest and sources of funding: This work was supported by the National Natural Science Foundation of China (no. 81771875). None declared to all authors. Correspondence to: Zhi Yang, PhD, Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), 52 Fucheng Rd, Haidian District, Beijing100142, China. E-mail: pekyz@163.com; and Yansong Lin, MD, PhD, Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, No. 1 Shuaifuyuan, Wangfujing St, Dongcheng District, Beijing 100730, China. E-mail: linyansong1968@163.com. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.

FDG PET/CT of Benign Psammomatous Meningioma Effacing the Medulla A 62-year-old woman had progressively developing throbbing right neck pain for 1 year. The pain radiated to the right suboccipital area, sometimes accompanied by breathlessness. To rule out cancer, patient received FDG PET/CT, which showed an intraspinal cord intense FDG-avid calcified mass at the level of the first cervical spine, mimicking malignancy. MRI showed it effacing the medulla; surgery is probably a challenge. She received laminectomy with tumor removal; pathology showed psammomatous meningioma, World Health Organization grade I. This case suggests that benign spinal cord psammomatous meningioma with calcification may show high FDG uptake, mimicking malignancy. Received for publication September 23, 2020; revision accepted November 5, 2020. Conflicts of interest and sources of funding: none declared. Correspondence to: Yuh-Feng Wang, MD, PhD, Department of Nuclear Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, No. 2, Minsheng Rd, Dalin Township, Chiayi 622, Taiwan, Republic of China. E-mail: yuhfeng@gmail.com. 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 © 2020 Wolters Kluwer Health, Inc. All rights reserved.

Ovarian Inflammation Mass Mimicking Recurrent Rectal Cancer 17 Years After Surgery: PET/CT and MRI Findings A 58-year-old woman diagnosed with rectal cancer received surgery and chemotherapy 17 years ago, and since then, she has been tumor-free. However, 1 month ago, she complained of progressive abdominal and pelvic pain. MRI scans revealed a soft-tissue ovarian mass with heterogeneous signals in the right pelvis, showing obvious enhancement after contrast injection. On PET/CT images, the lesion presented with intense FDG accumulation. Above imaging findings raised the possibility of tumor recurrence, and thus exploratory laparotomy was performed. Pathological results confirmed the diagnosis of active inflammation with fibrous tissue hyperplasia. Received for publication October 15, 2020; revision accepted November 1, 2020. Conflicts of interest and sources of funding: This study was supported by the National Natural Science Foundation of China (grants 81471692 and 81901776), project funded by the China Postdoctoral Science Foundation (grant 2019M650245), and Post-Doctor Research Project, West China Hospital, Sichuan University (grant 18HXBH070). None declared to both authors. Correspondence to: Anren Kuang, MD, Department of Nuclear Medicine, Laboratory of Clinical Nuclear Medicine, West China Hospital of Sichuan University, No. 37 Guoxue Alley, Chengdu 610041, China. E-mail: kuanganren@263.net. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.

Prognostic Value of Positive Presurgical FDG PET/CT in the Evaluation of Tumor-Induced Osteomalacia Objectives Tumor-induced osteomalacia (TIO), a rare paraneoplastic syndrome, is curable by excision or destruction of the causative tumor. However, occasionally, TIO may relapse after surgical intervention. We aimed to investigate the roles of 18F-FDG PET/CT in the prognosis of TIOs. Methods Seventy-six patients who had surgically removed tumors that caused osteomalacia were included in this retrospective investigation. All patients underwent both 18F-FDG and 68Ga-DOTATATE PET/CT prior to surgery. The prognostic value of presurgical FDG PET/CT study was determined with 5-year follow-up. Results In the presurgical evaluation, 68Ga-DOTATATE detected lesions in all 76 patients. However, FDG PET/CT was positive in only 25 among all 76 patients. Following surgical removal of the causative tumor, all 76 patients had symptomatic relief and normalization of the serum phosphate level initially. However, 15 of 76 cases (19.7%) had recurrent hypophosphatemia and became symptomatic again during the follow-up. Among these 15 patients with recurrence, 11 (73.3%) had recurrent lesions at the original location of the resected causative tumors, whereas 4 were in other locations due to malignant nature of the primary tumor. Interestingly, 14 of these 15 patients with recurrent disease had positive presurgical FDG PET/CT findings with an incident ratio of 56.0% (14 of 25). In contrast, only 1 patient with recurrent disease had negative presurgical FDG PET/CT scan with an incident ratio of 1.9% (1 of 51), significantly less than the positive presurgical FDG PET/CT group (P < 0.05). Conclusions A positive presurgical FDG PET/CT suggests increased likelihood for possible recurrence of TIO after surgical resection. In contrast, when a causative tumor detected by 68Ga-DOTATATE PET/CT does not have elevated activity on FDG PET/CT, the chance of recurrence is very small. Received for publication October 26, 2020; revision accepted November 2, 2020. Conflicts of interest and sources of funding: The authors declare that they have no conflict of interest. This report was funded by CAMS Innovation Fund for Medical Sciences (CAMS-2017-I2M-1-001). The requirement for informed consent was waived because this retrospective study used existing patient data and images. Correspondence to: Hongli Jing, MD, PhD, Department of Nuclear Medicine, Peking Union Medical College Hospital, No. 1 Shuaifuyuan, Wangfujing, Dongcheng District, Beijing 100730, China. E-mail: annsmile1976@sina.com; or Fang Li, MD, Department of Nuclear Medicine, Peking Union Medical College Hospital, No. 1 Shuaifuyuan, Wangfujing, Dongcheng District, Beijing 100730, China. E-mail: lifang@pumch.cn. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.

Reduced Myocardial Uptake of 123I-MIBG in Congenital Insensitivity to Pain With Anhidrosis A 30-year-old man presented with repeated episodes of painless injuries in his feet and abnormally high body temperature. He was diagnosed with congenital insensitivity to pain with anhidrosis—a rare hereditary peripheral neuropathy characterized by decreased pain, reduced sweating, and autonomic neuropathy. Congenital insensitivity to pain with anhidrosis is also called hereditary sensory and autonomic neuropathy type IV. 123I-MIBG myocardial scintigraphy showed reduced myocardial uptake (heart-to-mediastinum ratio: 1.56 and 1.42 in the early and late phases, respectively; washout ratio, 49%), indicating autonomic dysfunction. This finding may contribute to the diagnosis of congenital insensitivity to pain with anhidrosis and the semiquantitative evaluation of an autonomic dysfunction. Received for publication July 7, 2020; revision accepted October 29, 2020. Conflicts of interest and sources of funding: none declared. Correspondence to: Mihoko Sasahara, MD, Department of Radiology, Tokushima University Graduate School of Biomedical Sciences, 2-50-1 Kuramoto-cho, Tokushima 770-8503, Japan. E-mail: k.mihoko.928@gmail.com. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.

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Medicine by Alexandros G. Sfakianakis,Anapafseos 5 Agios Nikolaos 72100 Crete Greece,00302841026182,00306932607174,alsfakia@gmail.com,

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