A rare giant atrial septal cardiac blood cyst in an adult: a case report.

Background: Cardiac blood cysts are exceedingly rare cardiac tumours usually found on cardiac valves in infants. We report and discuss a rare unique case wherein a giant atrial septal cardiac blood cyst was found in an adult. Case summary: A 59-year-old Chinese lady with history of hypertension, hyperlipidemia and transient ischaemic attack presented with atypical chest pain. Her ECG suggested right ventricular strain. Echocardiography revealed a large right atrial intracardiac mass attached to the interatrial septum which prolapsed into the right ventricle during each cardiac cycle with associated dilatation of the right atrium and right ventricle. Computed tomography scans showed no evidence of malignancy or metastasis. Considering our patient's profile and the characteristics of the mass, it was opined to likely be a cardiac myxoma. After consultation with our cardiothoracic surgeons, she underwent surgical resection of the intracardiac mass. Histology revealed that the intracardiac mass was a cardiac blood cyst. Discussion: First described by Elsasser in 1844, cardiac blood cysts are extremely rare benign cardiac tumours very rarely seen in adults. Though benign, they have been associated with outflow tract obstruction, valvular regurgitation and embolization. Symptomatic patients do well with surgical resection, while long-term outcomes in asymptomatic patients followed up with serial echocardiograms are mixed. Due to its rarity, existing literature is limited to case reports and small case series, with a lack of guidelines on management till recently. Our case report serves to highlight this unique presentation of an exceedingly rare intracardiac tumour.