(~ASE REPOI~T Metastatic osteosarcoma in the inferior vena cava and the right atrium Abstractw.). Burger MBChB (Stell) Registrar at UOFS Osteosarcoma commonly metastasize to the lung, lymph nodes, liver and brain. In this case we describe a rare presentation of direct infiltration, by an osteosarcoma, of the iliac veins that continued into the inferior vena cava (Tv'C)and cou Id be seen up to the right atrium. Introduction Osteosarcoma metastases are common and may often present in an uncommon place and fashion. Meta- static cardiac tumours are more com- mon than primary sarcomas of the heart. The incidence is higher in chil- dren and young adults and the com- monest tumours to metastasize are Wilms' tumours and neuroblastomas. Other abdominal tumours, including secreting and non-secreting adrenal tumours, retroperitoneal sarcomas, hepatocellular carcinomas, teratomas and lymphomas, can involve the IVe. 10 SA JOURNAL OF RADIOLOGY- August 2000 There have been reports of metastatic osteosarcomas involving the IVC and cardiac chambers. Case report A 31-year-old black woman from Lesotho, southern Africa, presented with a local recurrence of osteosar- coma in her right leg approximately a year-and-a-half after initial diagno- sis. The patient had an above knee amputation in December 1998. One- and-a-half years later she presented with a swollen, firm amputation stump of her right leg. The patient looked chronically ill. The stump showed two small ulcers and a hard mass that could be palpated up to the inguinal area. The patient also had decreased movement of her right hip and on vaginal examination the uterus was immobile. A vague abdominal mass could be felt in the right lower quadrant. No clear lymphadenopathy was found but the patient was slightly anaemic clinically. Previous medical history The patient presented in Decem- ber 1998 with a swollen mass in her right distal femur that was histologically confirmed to be an os- teosarcoma and an above knee ampu- tation was performed. She received chemotherapy. Initially the chest x- ray showed no metastases, but she presented three months later with a single pulmonary nodule in her left lung. A metastatectomy was per- formed. Due to financial constraints , the patient was unable to attend the follow-up Oncology Clinic and pre- sented only six months later with a local recurrence in the area proximal to the amputation of her right leg. A to page 11 Metastatic osteosarcorna in the inferior vena cava and the right atrium (rom page 10 chest X-ray also showed new lung metastases in the right lung. (Fig. 1) The tumour was deemed to be unresectable and the patient received three courses of chemotherapy with mixed response. Again the patient had financial dif- ficulty and only arrived at the Oncol- ogy Clinic four months later. Initially, a scintigram was done that was nor- mal. The FBC, SMAC,VDRL, and HIV blood tests were normal. On the patient's last admission the chest X-ray showed three metastatic nodules in the right lung. Fig. 2 Pre-contrast CT pelvis. (A) The initial pre-contrast CT shows a mass with minimal calcifications in the right inguinal area. There are already signs of infiltration of the right femoral vein and collateral veins. Fig. 1 Chest X-ray with a single metastatic nodule in the right lung. A CT chest, abdomen and pelvis was done before and after intravenous contrast, using a GE spiral scanner with 7 mm slices and a pitch of 1,7. Oral gastrografin was also adminis- tered one hour before the examina- tion. The CT showed extensive local infiltration of the recurring osteosar- coma in the right upper thigh, in- guinal area and right pelvis. It was easily identified by the characteristic calcifications of the osteosarcoma. The bladder, uterus and rectum were displaced to the left. (Fig.2) Tumour thrombus filled the iliac vein and the IVC and could be traced up to the right atrium. There was clear (B) Six months later the CT was repeated and extensive infiltration into the soft tissue, right femoral vein and collateral veins are seen. The characteristic osteoid calcifications of osteosarcoma are easily identified. expansion of the IVC, especially in the upper abdomen. Infiltration of the IVC wall and extension beyond could not be excluded on CT. On the pre-con- trast study the tumour thrombus was filled with calcifications. The tumour thrombus could be seen as a hypo- dense filling defect, mixed with calci- fications in the IVC on the post con- trast studies. The tumour also infiltrated the col- lateral veins (ascending lumbar veins) that could be seen displacing the right psoasmuscle ventrally.Dilated collateral 11 SAJOURNAL OF RADIOLOGY- August 2000 veins could be seen through- out the abdomen. There was also hydro-nephrosis and hydro-ureter seen in the right kidney. The right kid- ney showed a decrease in contrast enhancement and a venous infarct was sus- pected. (FigJ) The spleen and portal vein appeared to be promi- nent. The CT chest showed eight small metastatic nod- ules (Fig.4), in both the up- per and lower lobes of the right lung. There were some postoperative pleuritic changes on the left from the previous metastatectomy. No clear infiltration of the endocardium of the right atrium could be shown. A prominent azygos vein was seen in the poste- rior mediastinum. No pleu- ral effusion, liver- or kidney- metastases could be seen. An ultrasound of the ab- domen was done that con- firmed the hydro-nephro- sis of the right kidney and Fig. 3 Post-contrast CT abdomen. An under enhanced right kidney with a dilated renal pelvis and a degree of hydro-nephrosis could be seen. topags 12 Metastatic osteosarcorna in the inferior vena cava and the right atrium /' -,~"-,'''', ,, ". ~ - ~~. ' ~/ Discontinuous tumour foci may be seen in bone mar- row in up to 10%. Other rare sites include the kid- neys,' skeletal muscles' and the NC and heart.' An iso- lated brain metastases of osteosarcoma in a patient presenting with a patent foramen ovale has been reported.' Tumour extension to the Ive represents an im- portant complication in abdominal carcinomas, al- though very rare in osteosarcomas. The pre-operative diagnosis of vena caval and cardiac involvement is an important consideration in surgical planning and future treatment. The surgical approach and procedure are dependent on the level of superior extension of the tumour thrombus. The following points should be clari- fied before surgery: • whether the NC is involved by tumour thrombus and, if so, the na- ture of the primary tumour; • the cranial limit of the tumour thrombus extension, whether it in- volves the intra-hepatic IVe, the hepatic veins, or the right atrium; and • the presence or absence of tu- mour invasion of the wall of the NC 6 In patients with musculoskeletal malignancies, thrombosis of the Ive may occur secondary to compression by adjacent adenopathy or by a paraneoplastic hypercoagulable state. Direct extension of the bone tumours into adjacent vessels is, however, rare. The site of tumour entrance into the vessels is not definitely known, al- though some speculate that with bone tumours the malignant cells enter the Fig. 4 Post-contrast CT chest. A single metastatic nodule Is seen on this slice In the right lung. The tumour thrombus extending into the right ventricle could also be seen. also showed a thrombus in the NC, stretching the whole of the IVC The thrombus could be visualised in the right atrium. Discussion Osteosarcoma is the most com- mon tumour of bone in adolescents and young adults and the second most common primary bone tumour after multiple myeloma. It accounts for ap- proximately 15% of all primary bone tumours confirmed at biopsy. There are numerous types of primary osteo- sarcomas, including intra medullary (high grade, telangiectatic, low grade, small cell, osteosarcornatosis, and gnathic), surface (intracortical, parosteal, periosteal and high grade surface), and extra-skeletal. I Approximately 2% of patients have metastases at presentation with osteosarcoma. The most common site for metastases is the lung (15%) via hematogenous spread. Other sites include lymph nodes, liver and brain. The metastatic lesions may be calcified, although this is rare (10%). Unlike Ewing's sarcoma, skel- etal metastases are uncommon (< 1%). 12 SAJOURNAL OF RADIOLOGY- August 2000 veins via intramedullary channels within the bone similar to the en- trance route of normal blood-form- ing elements." Since the number of patients who benefit from relapse therapy is still low, it remains to be shown whether an increased frequency of lung C'l- scans or MRls of the primary tumour site will improve early detection of relapse and, if so, whether that will enhance the chance for successful re- lapse treatment. Chest X-rays, lung CT and a clinical examination should be performed routinely for at least three years after completion of therapy or relapse diagnosis. In con- trast, bone scintigraphy and local X- rays appear not to be useful as rou- tine follow-up investigations.' References 1, Atra A, Shankar AG, Padhani AR, Metastatic cardiac osteosarcoma - imaging features, The British Journal of Radiology 1998' 71:336- 339. ' 2, Ogose A, Morita T, Emura I, Nemoto K Hirata Y. Osteosarcoma metastatic to th~ kidneys without lung involvement [Review [. Japanese Journal of Clinical Oncology 1999; 29(8):395-398, 3, Pe~ WC, Shek TW, Wang SC, Wong JW, Chien EP, Osteogenic sarcoma with skeletal muscle metastases, Skeletal Radiology 1999· 28(5):298-304. ' 4, Giuliano CT, Kauffman WM, Haller JO, Fletcher BO, Rao SP, Inferior vena cava-right atrium tumour thrombus in malignant pelvic bone tumours in children, Paediatric Radiology 1992; 22:206-208. 5. Menassa L, Haddad S, Aoun N, Slaba S, Atallah N. Isolated brain metastases in a patient with a patent foramen ovale, European Radiology 1997; 7(3):365-7. 6, Didier 0, Racle A, Etienvent JP, Weill F. Tumour thrombus of the inferior vena cava secondary to malignant abdominal neoplasms: US and CT evaluation, Radiology 1987;162:83-89. 7. Korholz D, Verheyen J, Kemperdick HF, Gobel U. Evaluation of follow-up investigations in osteosarcoma patients: Suggestions for an effective follow-up program. Medical and Paediatric Oncology 1998; 30(1): 52-8.