Use of FDG-PET Imaging for Patients with Disseminated Cancer of the Appendix

The goal of this study is to evaluate the use of positron emission tomography (PET) in evaluation of patients with peritoneal dissemination of carcinoma of appendiceal origin (PDA). Thirty-three patients with PDA, who had preoperative PET or PET/CT imaging, were analyzed. Using operative, pathology, and PET ± CT data, presence or absence of disease in each abdominal quadrant was noted and the use of 18fluoro-deoxy-glucose (FDG) PET for each quadrant was evaluated. The mean age was 52, and there were 17 males; 58 per cent had low-grade lesions. PET was positive in only 35 per cent of cases overall (30 and 41% sensitivity for low-grade and high-grade, respectively). PET without CT sensitivity for low-grade and high-grade lesions was 21 and 8 per cent, respectively. PET imaging has limited use for patients with PDA. We do not recommend the use of FDG-PET for patients with PDA from cancer of the appendix.

Use of FDG-PET imaging for patients with disseminated cancer of the appendix

The goal of this study is to evaluate the use of positron emission tomography (PET) in evaluation of patients with peritoneal dissemination of carcinoma of appendiceal origin (PDA). Thirty-three patients with PDA, who had preoperative PET or PET/CT imaging, were analyzed. Using operative, pathology, and PET +/- CT data, presence or absence of disease in each abdominal quadrant was noted and the use of 18fluoro-deoxy-glucose (FDG) PET for each quadrant was evaluated. The mean age was 52, and there were 17 males; 58 per cent had low-grade lesions. PET was positive in only 35 per cent of cases overall (30 and 41% sensitivity for low-grade and high-grade, respectively). PET without CT sensitivity for low-grade and high-grade lesions was 21 and 8 per cent, respectively. PET imaging has limited use for patients with PDA. We do not recommend the use of FDG-PET for patients with PDA from cancer of the appendix.

Testicular relapse of non-Hodgkin Lymphoma noted on FDG-PET

Testicular relapse of leukemia and lymphoma is a well-recognized phenomenon, with testicular relapse of lymphoma being more common in the adult population and leukemia relapse being more common in the pediatric population. With the advent of F-18 fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) in the evaluation of lymphoma it is possible to evaluate testicular uptake of FDG and to detect primary testicular lymphoma or testicular relapse on the FDG-PET examination. Testicular relapse of non-Hodgkin lymphoma (NHL) detected on FDG-PET has been reported previously. We report an additional case in which there was testicular activity at presentation, a response to therapy (orchiectomy not performed) and then testicular relapse followed by orchiectomy. We review the literature with regard to testicular recurrence and testicular uptake of FDG-PET. There have been studies that have examined normal standardized uptake value maximum (SUVmax) values in the testicle, with normal values ranging from 2.81 (30-39 years) to 2.18 (80-89 years), depending upon age. However, it should be noted that there could be considerable variability in SUVmax values depending upon the units used (e.g. normalized to lean body mass vs. body weight) and depending upon examination variables such as dietary conditions, muscle uptake or extravasation of FDG. Elevated activity or lateralizing activity should be viewed with suspicion, with etiologies including primary testicular tumor, primary or secondary testicular lymphoma and metastatic disease with other etiologies less likely.