18-F FDG PET/CT in a Case of Recurrent Pericardial Effusion Diagnosed as Cardiac Sarcoma

We present a case of recurrent pericardial effusion, in which 18 F- fluorodeoxyglucose positron emission tomography computed tomography (FDG PET CT) scan helped in clinching the diagnosis. A 22-year-old female presented to the civil hospital with cardiac tamponade and massive pericardial effusion. She underwent pericardiocentesis that aspirated approximately 1.5 L of hemorrhagic and exudative fluid. The patient was started on anti tubercular therapy (ATT) drugs and prednisolone and was discharged on the 6^th day after the pigtail was removed on the 5^th day with no aspirate and echo showing minimal pericardial effusion and thick strands. The patient was asymptomatic during the outpatient department follow-up. After 1 month, she again presented with massive pericardial effusion and cardiac tamponade. Pericardiocentesis aspirated approximately 750 ml of hemorrhagic fluid. The patient also had severe anemia. Cytology of pericardial fluid was suspicious of malignancy. The patient developed recurrent cardiac tamponade despite being on steroids and ATT. Therefore for further management and oncology workup, the patient was referred to a tertiary care center and CTVS consult for pericardial biopsy and pericardial window formation. On further investigation, the chest X-ray showed biventricular cardiomegaly, 2d-echo revealed massive pericardial effusion with septations suggestive of constrictive pericarditis. A high-resolution CT chest was done that showed pericardial effusion with postpericardiocentesis status, few necrotic mediastinal lymph nodes, consolidation in the left lung, and mild bilateral pleural effusion. Pericardial fluid analysis was hemorrhagic and exudative, and cytology revealed atypical cells with hyperchromatic nuclei and atypical mitosis. The culture sensitivity was sterile.

The patient was planned for FDG PET CT with dietary restriction of high fat, high protein, and low carbohydrate diet for 48 h, followed by a fasting period of 12 h. The scan revealed an ill-defined middle mediastinum mass with SUV max – 16.00, gross pericardial effusion with metabolic activity in the periphery and septations SUV max – 10.27 and a small highest mediastinal lymph node [Figure 1]. Mediastinal mass biopsy was done that proved it as high-grade sarcoma-FNCLCC Grade 3 [Figure 2].

Close

Figure 1 FDG PET CT image in the axial section of the thorax shows a hypermetabolic soft-tissue density well-defined lesion in the middle mediastinum region. There is peripheral FDG avidity along the pericardium with hypometabolic effusion areas and hypermetabolic septate areas. FDG: Fluorodeoxyglucose, PET CT: Positron emission tomography computed tomography

Export to PPT

Close

Figure 2 (a and b) H and E slide after anterior mediastinal biopsy shows tumor cells in diffuse sheets haphazardly arranged and interspersed with fibroadipose tissue, areas of fibrosis along with chronic inflammation. The tumor cells 18 are spindled to oval in shape. (c and d) Sections of mediastinal mass shows spindle to epitheloid cells in solid sheets with areas of formation of vascular channels. The malignant spindle cells are lining these channels. The epitheloid cells have abundant cytoplasm, large vascular nuclei and prominent eosinophilic nucleoli

Export to PPT

Primary anterior mediastinum high-grade sarcoma is a rare entity to be clinically experienced. The prognosis of mediastinum high-grade sarcoma is generally poor because of difficult surgical resection and partial response on chemotherapy and/or radiotherapy.[1]

About 25% of all cardiac tumors are primary malignant cases, while secondary cardiac tumors, are more frequent and due to metastatic spread or by direct invasion. Echocardiography and magnetic resonance imaging are the most used and sensitive techniques to detect and characterize suspected cardiac masses. FDG PET does not have an established role in the routine evaluation of cardiac tumors, which is probably due both to their low frequency and to the physiologically high uptake of FDG.[2]

Pericardial biopsy with standard sampling has a low diagnostic value for pericardial diseases. Extensive pericardial biopsy guided by pericardioscopy had better diagnostic value than pericardial biopsy guided by fluoroscopy.[3]

Primary malignant tumors affect ages from 30 to 50 years old, and they are usually sarcomas (angiosarcoma, rhabdomyosarcoma, leiomyosarcoma, liposarcoma, osteosarcoma, fibrosarcoma, and malignant fibrous histiocytoma). Metastatic cardiac tumors usually arise from melanomas, lung, breast, and renal cancer, as well as lymphomas.[4]