Role of 18F-FDG PET/CT in the metastatic workup of angiosarcoma.

Introduction: Angiosarcoma   is an uncommon malignancy characterized by rapidly proliferating anaplastic cells derived from blood vessels and lining irregular blood-filled spaces. They have high tendency to recur and metastasize. Proper diagnosis can help in the effective and timely treatment of angiosarcoma. 18F-FDG PET/CT can be used to evaluate the primary sites and metastases spread in these patients.

Methods: Clinicopathological and PET/CT imaging data of 13 angiosarcoma patients were collected and  evaluated  at our institute. Acquisition of 18F-FDG PET/CT was performed on dedicated PET/CT scanners (Biograph mCT, Siemens Inc and Discovery PET/CT, GE) 45-60 minutes after administration of 8-10mCi of radiotracer intravenously. The scans were interpreted by two experienced Nuclear Medicine Physicians and the primary site of localization and metastatic involvement was assessed.

Results: Out of the 13 patients there are 6 male and 7 female patients. The mean age of the patients was 44.9 ± 16.9 years with a range from 20 to 69 years. 7 patients underwent 18F-FDG PET/CT as part of baseline evaluation while the remaining 6 patients for response evaluation. Of the 6 patients ,three patient showed  progressive disease on follow up 18F-FDG PET/CT, and the remaining 3 patients revealed  either partial response (2 patients) or stable disease (1 patient) on 18F-FDG PET/CT. Sites of  primary tumor localization were heart (4/13), breast (3/13),foot(3/13),thyroid(1/13),spleen(1/13) and face(1/13). Most common areas of metastatic foci that were detected on 18F-FDG PET/CT were to lymph nodes in 4 patients, bone in 2 patients and adrenals in 2 patients with other less common areas of involvement as liver, lungs, adrenals and spleen. 18F-FDG PET/CT detected most common primary and metastatic sites as heart (30%) and lymph nodes (30%) respectively.

Conclusions: 18F-FDG PET/CT exhibited a crucial role in the metastatic work up of rare malignancy like angiosarcoma during baseline evaluation as well as for response assessment to therapy. Thus providing a proper insight into the tumor behaviour of angiosarcoma, with information on common sites of primary and metastases.