Cryptorchidism as a potential source of misinterpretation in 18FDG-PET imaging in restaging lymphoma patients

Incidental Detection of Urinary Bladder Herniation in 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Mimicking as Metastatic Deposit in the Inguinal Canal

Although ¹⁸F-fluorodeoxyglucose (FDG) is the most extensively used tracer in oncological positron emission tomography/computed tomography (PET/CT) studies, various physiological as well as benign pathological conditions are known to cause false-positive results. This report describes ¹⁸F-FDG PET/CT done in an elderly man with primary hepatocellular carcinoma, revealing a metastasis mimicking lesion in the left inguinal canal, which was identified as the herniated portion of the urinary bladder. Though rare, bladder herniation, especially with a narrow neck, can be a pitfall in the evaluation for metastatic disease. The study also highlights the utility of delayed imaging in the evaluation of pelvic pathology.

The independent functioning of the orchidopexied congenital undescended testis as assessed by positron emission tomography/computed tomography

Fertility after orchidopexied undescended testes (UDT) is impaired. Although fertility parameters are known to be more favorable in unilateral cases than in bilateral cases, the exact contribution of the unilateral orchidopexied UDT to fertility is unknown. We used testicular ¹⁸F-fluoro-2-deoxyglucose (¹⁸F-FDG)-uptake assessed by positron emission tomography/computed tomography (PET/CT) to investigate the function of the orchidopexied unilateral congenital UDT, compared to its normally descended counterpart. We hypothesize that the contribution of the orchidopexied unilateral congenital UDT to fertility in adulthood is low. Eleven men who underwent orchidopexy for congenital UDT at the age of 1.9 ± 1.4 (range, 4.5 months -4.0) years were seen in follow-up at the age of 24.1 ± 2.3 (20.6-28.0) years. All underwent physical examination, testicular ultrasonography and PET/CT. Testicular ¹⁸F-FDG-uptake was expressed as the peak Standardized Uptake Value (SUV_peak). The mean SUV_peak of the orchidopexied UDT was 2.74 ± 0.48 (2.13-3.47), which was significantly lower than its counterpart (P = 0.021). Besides, there was no correlation between the testicular volume and the SUV_peak. The orchidopexied congenital UDT has been shown to be less metabolically active than its contralateral counterpart. Nevertheless, we suggest that the operated testes function to some degree.

Pelvis: normal variants and benign findings in FDG-PET/CT imaging

With the widespread use of whole-body fluorodeoxyglucose (FDG)-PET/computed tomography as a diagnostic tool in patients with cancer, incidental findings are of increasing importance. This is particularly true within the pelvis, where several benign findings might present with increased FDG uptake. In addition, physiologic excretion of radiotracer by way of the urinary tract can complicate image analysis. This article reviews potential incidental benign findings in the pelvis that one should be aware of when interpreting FDG-PET/computed tomography scans.