A 32-year-old woman was referred at 32 weeks gestation after a fetal cardiac tumour was detected at an obstetrical ultrasonic examination. A detailed fetal echocardiographic study at our centre confirmed the finding, demonstrating a large, inhomogenous fetal cardiac mass (delineated by arrows), which filled most of the right atrium and was causing obstruction to the right ventricular inflow (Fig. 1). Sustained atrial ectopic tachycardia prompted an expeditious delivery by Caesarean section 2 weeks later, the tachycardia then being controlled on esmolol. Postnatal magnetic resonance suggested an atrial haemangioma as the most likely diagnosis. The post-gadolinium T1-weighted axial magnetic resonance images (Fig. 2) showed regions of haemorrhage or thrombus within the centre (*), and enhancement of the outer regions of the tumour, confirming its vascularization. On the third day of life, surgical debulking was attempted to improve flow through the right ventricular inlet, but only two-fifths of the mass could be excised, due to adherence to the atrioventricular groove, the right coronary artery, and the coronary sinus, respectively. Histology suggested either haematoma or organized thrombus. Extensive thromboses of the upper systemic veins, resistant to therapy, complicated the post-operative course, while enterococcal septicaemia led to further deterioration. The baby eventually died at 6 weeks of age. The autopsy specimen (Fig. 3) shows the residual tumour mass (delineated by arrows) within the right atrial wall, abutting the atrioventricular groove. Histology confirmed the diagnosis of an infantile type of haemangioendothelioma. The microscopic view (Fig. 4; magnification 100×; hematoxylin and eosin) demonstrates clusters of endothelial cells, some of which have formed vascular channels, within a fibrous stroma. The insert (400× magnified) shows occasional cells with cytoplasmic vacuoles and mild nuclear pleomorphism. Haemosiderin-laden macrophages are present in the upper portion. The endothelial cells were strongly positive for the endothelial marker CD34 (not shown).

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To the best of our knowledge, this is the first prenatally detected case of a cardiac haemangioendothelioma. This exceedingly rare tumour is potentially malignant, and carries a guarded prognosis. The mainstay of treatment remains surgical debulking in symptomatic cases, while the role of steroids, radiation, chemotherapy, and alpha–interferon is uncertain.