Primary cardiac hemangioendothelioma: a case report

Primary cardiac hemangioendothelioma is extremely rare.1–3 Up to now less than twenty cases have been reported in English literature, the data about this kind of cardiac tumors are scanty. In this report, a case of a huge hemangio-endothelioma that arose from the right atrium and was successfully resected is presented. CASE REPORT A 36-year-old woman who complained of progressive shortness of breath for two years and being difficult on supine position for 2 months was admitted to the hospital on Octorber 15, 2005. She previously had been healthy, and no special medical history was noted. On physical examination, the cardiac border enlarged on both sides on percussion but no heart murmurs or cyanosis was found, and the liver was not palpable. Blood examination showed an elevated serum fibrin (714.5 ng/ml) and a slight anemia (hemoglobin 104.0 g/L). The tumor-related antigens carcinoembryonic antigen (CEA) and alpha-fetus protein (AFP) were in the normal range. Chest X-ray films showed cardiomegaly and the cardiac echocardiography displayed that the right atrium was filled by a 3.9 cm ×4.09 cm solid mass attached to the top and lateral of the right atrium. However, the atrial septum and the tricuspid valve were spared. No abnormal movement of the valves was found (Fig. A). Computed tomography revealed effusion in the pericardial and bilateral thoracic cavity.Fig. A.: The echocardiogram showed a solid mass in the right atrium.At operation, the pericardium was found to be thickened, and the parietal pericardium adhered to the visceral. There were a little bloody pericardial effusion and a moderate amount in bilateral thoracic cavity. The cardiac tumor was located between the crista terminnalis, right auricle and tricuspid valve ring, tightly attached to the lateral wall of the right atrium, and had a rather broad base. The tumor size was about 5 cm×5 cm×6 cm. The tumor mass was resected with a part of the atrium wall, which was repaired by the autopericardium. Pathological examination revealed that the neoplasm was covered with massive coagulated blood. The tumor was composed of short strands, cords or solid nests of round to slightly spindle-shaped cells with round or ovid nuclei and prominent cytoplasmic vacuolization, some of which formed vascular channels (Fig. B). The neoplastic cells with fairly bland appearance had a few mitoses, but exhibited an infiltrative growth pattern at the tumor periphery, compressing the cardiac muscle cells, which became atrophic (Fig. C). Immuno-histochemically, the tumor cells either forming vascular channels or disposed in solid sheets expressed the factor VIII-related antigen, CD31 and CD34 (Fig. D), however, were negative for cytokeratin, desmin, CD117, mesothelial cell and calretinin. That confirmed the angiogenic nature of this primary cardiac tumor. Ki67 labeling index was rather high, approximately 30% (Fig. E). The postoperation course was uneventful with clinical improvement. The patient was discharged from the hospital on Octorber 25, 2005. The patient was asymptomatic and recovered well at the follow up three months later.Fig. B.: Vascular channels lined by round or surrouned by tumor cells with frequent cytoplasmic vacuoli-zation (HE, original magni-fication ×400).Fig. C.: Cardiac muscle cell are compressed and atrophic between proliferating vascular channels(HE, original magnification ×200).Fig. D.: Positive immunostaining of CD34 of the tumor cells (IHC, original magnification ×100).Fig. E.: Positive immunostaining of Ki-67 of the tumor cells (IHC, original magnification × 100).DISCUSSION Cardiac neoplasms may be primary or secondary. Although metastatic tumors of the heart are 30 times more common than the primary ones, most of the latter are benign, only 30% of them exhibiting signs of malignant.4 Among the primary cardiac tumors, myxoma is the most common neoplasm whereas vascular tumor— hemangioendothelioma is an uncommon vascular tumor which often present in soft tissue and is known to occasionally metastasize. Hemangioen-dothelioma arising from the heart is very rare,5 to our knowledge less than twenty cases have been previously reported in English literature.1–4,6–8 Patients with intracardiac masses may present with dyspnea on exertion, thrombembolic events, arrhythmias, pericarditis or congestive heart failure. Sometimes on the echocardiography and magnetic resonance imaging, it is difficult to distinguish a cardiac hemangio- endothelioma from a cardiac hemangioma and from a cardiac myxoma, both of which are important differential diagnostic considerations. Hemangiomas are usually circumscribed and intracavity solitary mass, particularly on magnetic resonance imaging, which is the most sensitive to tissue infiltration, with non-infiltrative appearance. That suggest the neoplasm is benign, but a specific diagnosis can not be made with imaging. However, cardiac myxomas typically appear as a mobile mass attached to the endocardical surface by a narrow stalk, which can be diagnosed by echocardiography and further imaging. If the narrow stalk is invisible, the diagnosis can not made by echocardiography and further imaging. In addition, metastatic carcinoma should be considered in the differential diagnosis. Cardiac hemangioma is a benign tumor whereas cardiac hemangioepithelioma and cardiac myxoma can recur and metastasize. So a correct pathological diagnosis is very important. Cardiac hemangioendothelioma is classified as a low-grade malignant neoplasm. Up to now the pathogenesis of this rare disorder is unknown, but this tumor usually originates from the subendo-cardium and may occur at any part of the heart. It has been reported that most of patients with cardiac henangioendothelioma after resection have a favorable outcome whereas radiation therapy and chemotherapy have only limited effect on the tumor.8 In the present case, the tumor was successfully resected with no other additional therapy. The patient was followed up about three months with no sign of recurrence or metastasis. In view of the low grade malignancy, and the infiltrative growth pattern of this tumor, further close follow-up seems to be necessary. Acknowledgement: We are grateful to professor WANG Wu-ru of the Harbin Medical University for the consultation.