Manish Dhyani MBBS, Presenter: Nothing to Disclose

Michael Stanley Gee MD, PhD, Abstract Co-Author: Nothing to Disclose

Anuradha Samir Shenoy-Bhangle MD, Abstract Co-Author: Nothing to Disclose

Peter F. Hahn MD, PhD, Abstract Co-Author: Stockholder, Abbott Laboratories Stockholder, Covidien AG Stockholder, CVS Caremark Corporation Stockholder, Kimberly-Clark Corporation Stockholder, Landauer, Inc

We undertook this study to determine the negative predictive value of PET for splenic lesions. Although PET has been used extensively for evaluation of space-occupying lesions in other organs, the current medical literature is contradictory on the current role of 18F-FDG-PET for characterization of splenic masses. Some studies have demonstrated high accuracy with good sensitivity and specificity when clinical data was used as the gold standard while others have demonstrated poor accuracy when histopathology was used as a gold standard.  

In this IRB approved single center retrospective study we searched an institutional database and reviewed imaging of all patients with a focal splenic lesion >6mm who had undergone an FDG-PET/CT scan with or without IV contrast. Splenic lesions with at least one-year follow-up and had metabolic activity less than or similar to the remainder of the spleen were identified. Lesions that exhibited >30% increase on the follow-up study were categorized as aggressive and included in the study.

Twenty-four subjects (M:F = 15:9) with a mean age of 55 years (mean = 21-80 years) with one or more PET-negative splenic lesions were identified to have aggressive splenic lesions on subsequent studies. 22 of 24 had a primary extra-splenic or systemic malignancy The most common primary malignancy in this cohort of patients was lymphoma (n=6, 25%) followed by lung cancer (n=5, 21%) and melanoma (n=3, 12.5%). Two of the lesions were primary splenic tumors (follicular dendritic cell tumor, littoral cell angioma); the other 8 arose in patients with extra-splenic malignancy and were clinically considered metastases.

Aggressive PET-negative lesions can arise in the spleen.

Low metabolic activity as determined by FDG-PET cannot be used alone to exclude aggressive behavior of a splenic lesion.

Dhyani, M, Gee, M, Shenoy-Bhangle, A, Hahn, P, Can We Ignore Spleen Lesions that Are Not Metabolically Active?.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13029091.html