Role of 18F-FDG PET-CT in Epitheloid Hemangioendothelioma

492 Aim: Assessment of role of 18F-FDG PET/CT in epitheloid hemangioendothelioma (EHE). EHE is a rare tumor of vascular origin, with borderline biological behavior and potential for metastases and multifocality. Localization of sites of disease involvement can aid in planning treatment options. Materials and Methods: This retrospective evaluated 18F- FDG PET-CTstudies of 15 patients with radiological (contrast enhanced CT/MRI) and histopathologically proven EHE. PET/CT images were acquired after intravenous administration of 7-10mCi of 18F-FDG and images were acquired at 45-60 minutes at 2 minutes per bed position. Baseline PET/CT scans were available in 15 patients and follow up PET/CT for post treatment response evaluation was available in 5 patients. Semi-quantitative analysis was done by calculating Standardized uptake value (SUVmax) of primary lesions. Results: 18F-FDG PET/CT scan data of 15 patients (7 male; 8 female) with EHE was retrospectively evaluated. Mean age of patients was 30.86±15.62 years. Site of primary lesion was liver (6 patients, mean SUVmax=11.4); paravertebral (2; mean SUVmax=4.4); bone (4; mean SUVmax=4.75); breast (1; SUVmax=3.6); abdomen (1; SUVmax=20.5) and gingiva (1; SUVmax=1.29). Involvement of both lobes of liver was observed in all 6 patients of liver EHE. Also, 5/6 liver EHE patients had nodal metastasis, 2/6 had lung metastasis and single skeletal, prostate and rectal wall lesions were observed in 3/6 patients. In 4 patients with skeletal EHE, 3 did not have metastasis while 1 had multifocal primary in tibia and multiple bones of foot along with additional findings of popliteal, inguinal and pelvic nodal metastases was detected on PET/CT scan. In2 patients with paravertebral EHE, additional findings of skeletal metastasis were observed while 1 of the 2 patients also had lung metastasis. In patient with gingiva and breast EHE, PET/CT was able to detect nodal metastasis and skeletal metastasis respectively, addition to the primary. In patient with jejunal EHE with multiple mesenteric lymph nodes, additional lesion was present in liver suggesting multifocal primary/metastasis. In 12 of 15 patients (80%) patients, PET/CT scan changed the course of management owing to the additional findings detected on scan. In 5 patients with follow up scan, 1 patient had disease progression, 2 had partial response while 2 had stable disease. Conclusions: 18F-FDG PET/CT has a high diagnostic performance in disease staging and restaging in patients of EHE and can aid in accurate treatment planning.