{"paper_id":"d276a085-291f-43fd-86f5-9aac31ab97f3","body_text":" Corresponding author: WS Felix Wong \nDepartment of Obstetrics and Gynaecology, School of Women’s and Children’s Health, The University of New South Wales, Sydney, \nAustralia (ORCiD 0000-0002-7256-1371). \nCopyright © 2022 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. \nFalse-positive diagnosis of uterine malignancy with raised 18F-fluorodeoxyglucose \nactivity in adenomyosis: A case report  \nWu Shun Felix Wong 1, * and Kwok To Thomas Li 2 \n1 Department of Obstetrics and Gynaecology, School of Women’s and Children’s Health, The University of New South Wales, \nSydney, Australia. \n2 Department of Obstetrics and Gynaecology, Queen Mary Hospital, The University of Hong Kong, China. \nWorld Journal of Advanced Research and Reviews, 2022, 13(02), 367–370 \nPublication history: Received on 18 January 2022; revised on 19 February 2022; accepted on 21 February 2022 \nArticle DOI: https://doi.org/10.30574/wjarr.2022.13.2.0178 \nAbstract \nPositron Emission Tomography - Computed Tomography (PET-CT) has been used to diagnose malignancy before \nsurgery. However, there may be an increase in 18F-fluorodeoxyglucose (FDG) uptake in PET scans in benign conditions, \nleading to a false-positive diagnosis of malignancy and unnecessary surgery. This PET-CT investigation is expensive and \nis not without risk, including radiation and drug or contrast hypersensitivity. Although variable uterine uptakes of FDG \nactivities in PET-CT had been reported in the literature, unawareness of its possibility in benign conditions could lead \nto a false alarm of malignancy. This paper reported a patient with a false-positive FDG finding presenting as a malignant \nuterine lesion for surgery, aiming to raise the clinical awareness of this finding. \nKeywords: False-positive diagnosis; PET-CT; Adenomyosis; 18 F-fluorodeoxyglucose; Raised CA125  \n1. Introduction\nComputed Tomography (CT) scan with contrast and fine cut in a suspected lesion to diagnose malignancy is the gold \nstandard before PET-CT has replaced CT scans for such purposes. It is also common to use PET-CT to diagnose \ngynaecological malignancy before surgery [1]. However, there may be an increase in 18F-fluorodeoxyglucose (FDG) \nuptake in benign uterine conditions [2]. It was reported that adenomyosis generally showed mild FDG uptake in \npremenopausal women; higher uptake was also sometimes seen during menstruation and ovulation [3]. Wong 2017 \nhad reported a case of false-positive PDG positron emission / computed tomography diagnosis of pelvic lymph node \nrecurrence following surgical treatment of Stage 1 endometrial cancer [4]. It was due to an ovulatory ovary. This had \nled to a false alarm and unnecessary surgery.  \nDr Yu et al. 2011 described variable uterine uptakes of FDG activities in PET- CT when they reported a 44-year-old \nwoman with adenomyosis showing increased FDG uptake mimicking malignant tumours during concurrent chemo-\nradiation therapy for cervical cancer [5]. PET-CT has been arranged to rule out malignancy whenever available in many \nhospitals. It is almost mandatory for the planning and management of cancer. However, this investigation is expensive \nand is not without risk, including radiation and drug or contrast hypersensitivity. This paper would like to highlight a \npatient with a false-positive FDG finding presenting as a malignant uterine lesion for surgery to raise the clinical \nawareness of this condition.  \n\n\nWorld Journal of Advanced Research and Reviews, 2022, 13(02), 367–370 \n368 \n2. Case report  \nA 40-year-old nulliparous patient had a history of left ovarian cystecto my performed in January 2019. In August 2020, \nshe presented with a recurrent left ovarian cyst, enlarged 12 weeks size uterus, menorrhagia and severe dysmenorrhea; \nshe was offered surgery for ovarian cystectomy and myomectomy in a private hospital. However, due to extensive pelvic \nbowel adhesion, only left ovarian cystectomy and salpingectomy could be performed. The pathology confirmed an \nendometriotic cyst and hydrosalpinx. Her postoperative course was complicated by left deep vein thrombosis (DVT) \nand pulmonary embolism, treated with anticoagulants (Clexane, Atixaba). She sought treatment again for abdominal \ndistension, pelvic pain, menorrhagia and severe anaemia in November 2021. An enlarged 28 weeks uterus on pelvic \nultrasound examination showed a large posterior adenomyoma (7.7 cm x 5.7 cm x 6.9 cm) and a large multiloculated \nhypoechoic cyst (11.3 cm x 7.4 cm x 7.8 cm). Her CA 125 was raised to 552 U/ml, and her haemoglobin was 6.3 g/dL. \nShe requested a second opinion of management.  \nA PET-CT was ordered to exclude malignancy because of the rapidly enlarged uterus and ovarian cyst. The PET-CT found \nan enlarged uterus with an ill -defined hypodense mass and moderate metabolic activity at the posterior uterine wall \nmeasuring 9.43 cm x 7.52 cm x 10.96 cm. The  radiological features suggested underlying malignant lesions with \nadenomyoma. The right large multiloculated hypodense cystic lesion (16.9 cm x 9.12 cm) showed multiple septations, \nno internal calcification, no solid component or fat density.  \n \nFigure 1 A PET CT showed an enlarged uterus up to the level of the umbilicus. Ill -defined CT hypodense mass with \nmoderate FDG metabolic activity is seen at the posterior uterine wall measuring 9.43 cm x 7.52 cm x 10.96 cm. The \nradiological features suggested underl ying malignant lesions with adenomyoma. The right large multiloculated \nhypodense cystic lesion (16.96 cm x 9.12cm) showed multiple septations, no internal calcification, no solid component \nor fat density \nGiven her severe anaemia, dysmenorrhoea and suspecte d uterine malignancy, she was counselled for hysterectomy, \nright salpingo-oophorectomy and bowel adhesiolysis. Blood transfusion and proper bowel were done before surgery. A \ntotal hysterectomy with right salpingo -oophorectomy was performed after laborious bowel adhesiolysis. A frozen \nsection of the uterus showed an adenomyoma and fibroids (figure 2). The surgery took 2.5 hours with a total blood loss \n\n\nWorld Journal of Advanced Research and Reviews, 2022, 13(02), 367–370 \n369 \nof 2000 ml. She recovered well, and she was discharged home on day 7 post -operatively. She was given oral \nanticoagulant Xarelto 20 mg daily for five weeks. \n \nFigure 2 A large uterine adenomyoma with multiple small fibroids with no pathological features of malignancy  \n3. Discussion  \nIn the clinical management of gynaecological patients, demographic data, clinical his tory, examination, appropriate \ninvestigations, and imaging are important to point toward the most likely diagnosis and the planning for subsequent \nmanagement. PET-CT is now used extensively for staging and monitoring patients with malignancy. It also helps  the \npre-operative diagnosis of malignancy by reviewing the nature of the tumour to determine the types of surgery and the \nneed for adjuvant therapy in malignancy at pre-operative counselling. PET-CT’s principle of action is based on the high \nglucose metabolism of malignant lesions; then, the 18F -fluorodeoxyglucose (FDG) generally accumulates in malignant \nlesions. However, FDG uptake is not specific for cancer cells, and increased uptake also occurs in actively growing cells \nor inflammatory cells. Therefore, it may result in a false-positive diagnosis of malignancy.  \nThe accurate interpretation of raised PDG activities remains a challenge to doctors, especially when the physiology and \npathophysiology of findings on FDG -PET/CT are not well understood. The aut hor reported a previous false -positive \nPET-CT case due to a physiologically ovulatory ovary [4]. Uterine adenomyosis in a premenopausal woman can also \nresult in false -positive 18FDG -PET [2]; thus, the paper aims to alert doctors of this possibility to help delineate the \ndiagnosis and guide subsequent surgery.  \nIn our case, the factors contributing to the increased FDG accumulation in the adenomyoma may include increased \nvascularity of the adenomyosis, presence of inflammatory cells, and a high number of rapidly growing cells per volume \nof the adenomyoma. In our patient, her surgery was necessary despite the false -positive diagnosis of uterine \nmalignancy. Her menstrual symptoms, severe anaemia, and large ovarian cyst found her surgery necessary. We had \ndone the appropriate preparations for bowel adhesiolysis, prev ention of DVT and intraoperative frozen section; \ntherefore, her surgery could be safely performed, and she recovered quickly from her suffering. In other cases with \nsimilar PET CT findings, it is important to assist the PET-CT diagnosis of malignancy by various means, i.e. clinical, other \nimaging, surgery, and a prior biopsy or frozen section during surgery would be recommended. Finally, a piece of advice \nto interpret whole -body PET-CT imaging is to consider the various physiological and technical factors t hat can affect \nFDG uptake that had been widely reported in the literature [2, 6].  \n4. Conclusion \nPET CT utilization has been ever-increasing. Other than the cost, radiation and availability, a false -positive diagnosis of \nmalignancy seems to be one of the most important aspects that warren further investigations and enhancement. Our \n\n\nWorld Journal of Advanced Research and Reviews, 2022, 13(02), 367–370 \n370 \ncase report and the previous one could help raise arousal for clinicians and radiologists of such an important issue. \nGiven the above, there is a need for further development in PET-CT in future.  \nCompliance with ethical standards \nDisclosure of conflict of interest \nBoth authors declare no conflict of interest. \nStatement of informed consent \nInformed consent was obtained from the patient in this paper. \nReferences \n[1] Narayanan P, Sahdev A. The role of (18)F -FDG PET CT in common gynaecological  malignancies. The British \njournal of radiology. 2017; 90(1079): 20170283. \n[2] Liu Y, Ghesani NV, Zuckier LS. Physiology and Pathophysiology of Incidental Findings Detected on 18F -\nFluorodeoxyglucose-Position Emission Tomography Scintigraphy. Seminars Nuclear Medicine. 2010; 40(4):294-\n315.  \n[3] Kitajima K, Murakami K, Kaji Y, Sugimura K. Spectrum of FDG PET/CT findings of uterine tumors. American \nJournal of Roentgenology. 2010; 195(3): 737-743. \n[4] Wong WSF. A false positive fluorodeoxyglucose positron emission tomography/computed tomography diagnosis \nof pelvic lymph node recurrence following surgical treatment of Stage 1 endometrial cancer - a case report. \nGynecology and Minimally Invasive Therapy. 2017; 6: 123–125. \n[5] Yu JI, Huh SJ, Kim YI, Kim T-J, Park BK. Variable uterine uptake of FDG in adenomyosis during concurrent chemo-\nradiation therapy for cervical cancer. Radiation Oncology Journal. 2011; 29(3): 214 -217. \n[6] Boellaard R. Standards for PET image acquisition and quantitative data analysis. Journal of nuclear me dicine. \n2009; 50(1): 11S-20S.  \nAuthor’s short Biography \n \nProfessor Felix Wong is a retired Professor at the University of New South Wales. He is renowned \nfor his contribution to medical education in Asia Pacific Countries. For his contribution and \nachievement in Endoscopic surgery, he was awarded the Lifetime Achievement Award by APAGE \nin 2017 and the Outstanding Contribution Award by the ESGE in 2018. Professor Wong has \npublished 14 books and more than 240 papers in local and international journals.","source_license":"CC0","license_restricted":false}