Interference of Known or Suspected Endometriosis in Reporting FDG PET/CT Performed in Another Indication

Abstract

Introduction: Endometriosis is a common gynecologic condition that may be visualized on 18 F-FDG PET/CT and mimic lesions of malignancy. We analyzed the interference of known or suspected endometriosis in reporting 18 F-FDG PET/CT performed in another indication. Results: The PET/CT images of 18 women with known (n = 15) or suspected (n = 3) endometriosis were analyzed. Based on clinical follow-up and results of other imaging, biopsy, and/or postsurgical histology, the presence of lesions of endometriosis at the time of 18 F-FDG PET/CT was confirmed in 13 of 18 patients (72%). The per-patient positivity rate of 18 F-FDG PET/CT was 8/18 (44%; 95% confidence interval, 22%-69%). The patient-based detection rate of 18 F-FDG PET/CT in patients with confirmed lesions of endometriosis was 8/13 (62%; confidence interval, 32%-86%). On per-lesion/site basis, 18 F-FDG PET/CT detected 11 of 20 sites (55%) of endometriosis. The SUVmax of these lesions/sites ranged between 1.8 and 5.3 (median, 3.8). In 9 of 18 patients (50%), a total of 13 non-endometriosis-related lesions/sites were detected by 18 F-FDG PET/CT; their SUVmax ranged between 2.7 and 23 (median, 9.4). Conclusion:The interference of known or suspected endometriosis in reporting 18 F-FDG PET/CT performed in another indication was limited but possible and should be kept in mind, even in postmenopausal women, as the oldest patient with 18 F-FDG-positive endometriosis was aged 63 years. The lesions of endometriosis showed inconstant 18 F-FDG uptake with overlap of SUVmax with low-grade malignancies. In our series, the greatest SUVmax value of lesion of endometriosis was 5.3, somewhat higher than the threshold of 4 previously proposed for identification of malignant transformation of endometriosis.

The role of PET/CT in oncogynecology (literature review)

“…В некоторых исследованиях описан аномальный характер поглощения ФДГ при эндометриозе, однако в большинстве эндометриоидных поражений нет специфического поглощения ФДГ [61]. Таким образом, ПЭТ/КТ с ФДГ не подходит для диагностики или стадирования эндометриоза.…”

Advances in Imaging for Assessing Pelvic Endometriosis

“…Although performed in small study populations and mainly in the case of extragenital endometriosis, positron emission tomography–computed tomography with 16α-[18F]fluoro-17β-estradiol (FDG PET/CT) was proposed as a feasible technique [ 121 , 122 ]. In addition, Balogova et al stated that, in some cases, the presence of endometriosis interferes with the FDG PET/CT performed for another indication [ 123 ].…”

Extrauterine Endometrial Stromal Sarcoma Mimicking Colorectal Cancer With Metastases

“…3,4 18 F-FDG PET/CT may be helpful in distinguishing malignant transformations in endometriosis with significant FDG uptake. [5][6][7][8] A low-grade EESS originating from the mesentery has been reported based on 18 F-FDG PET/CT with an SUV max of 4.5. 9 We describe a patient having multifocal low-grade EESS with colorectum involvement mimicking malignancy with wide metastases on 18 F-FDG PET/CT, which should be carefully distinguished from colorectal cancers.…”

“…Malignant transformation of endometriosis lesions mostly include endometrioid adenocarcinoma or clear cell carcinoma and in extremely rare case EESS originating from the mesenchyme 3,4 . 18 F-FDG PET/CT may be helpful in distinguishing malignant transformations in endometriosis with significant FDG uptake 5–8 . A low-grade EESS originating from the mesentery has been reported based on 18 F-FDG PET/CT with an SUV max of 4.5 9 .…”