A rare case of multiple inflammatory myofibroblastic tumors (IMT) of the liver and spleen: The findings on F-18 FDG-PET/CT

Learning Objectives 1. To report the findings on FDG-PET/CT and contrast-enhanced CT of a rare case of IMT in the liver and spleen. 2 .To review the characteristics of IMTs on FDG-PET/CT and CT. FDG accumulation and CT findings are variable because it depends on the varying amounts of inflammatory cells and the fibrotic component. 3.To realize IMTs as FDG-avid benign tumors may mimic malignant tumors , especially in patients with symptoms of a malignancy, such as weight loss and anaemia. 4. FDG-PET/CT combined with contrast-enhanced CT is helpful to distinguish IMT from other tumors. FDG-PET/CT as a systemic search can exclude malignant lesions in other sites and find recurrence and metastases.

A 44-year-old woman presented with weight loss and left abdominal pain . Laboratory findings revealed anemia , some liver function tests slightly elevated . The CT scan revealed two hypodense masses in the left and right lobe of the liver and one mass in the spleen. The lesions in liver were characterized by mild peripheral rim-like and septal enhancement on arterial phase. During delayed phase ,a gradual enhancement from the periphery to the center was noted, with hypoattenuating peripheral ring and a poor enhanced central satellite area.The splenic lesion also showed a gradual enhancement from the periphery to the center during a dynamic scan. Notable increased accumulation of FDG was observed on PET/CT.The maximum standard uptake values (SUVmax) of the tumors in spleen ,left and right lobe of the liver were 11.1, 12.9 and 12.5 respectively. The accumulation was more intense in the peripheral portion than in the central portion of the tumour. IMTs were diagnosed histologically. 5 months later , on PET-CT ,several avid accumulation of FDG lesions were observed on the capsule , inside and at the margin of the resection of the liver, spleen area , right side pleura, mediastinallymphnodes and right chest soft tisssue. The SUVmax range of all these lesions was from 3.8to 16.0