An unusual shaped mass filling the right cardiac chambers in a woman with a vascular malformation

Dear Editor, A-52-year-old female patient was admitted for uncontrolled arterial hypertension and non-sustained palpitations.
The echocardiography revealed an elongated, ring-shaped, highly mobile intracardiac mass apparently extending from the inferior vena cava into the right atrium and penetrating the tricuspid valve into the right ventricle, impairing closure of the tricuspid valve and causing mild tricuspid regurgitation (Fig. 1A). No other abnormalities were found by transthoracic and transoesophageal echocardiography while cardiac magnetic resonance imaging was inconclusive due to the high mobility of the intracardiac mass. Abdominal contrast – computed tomography showed filling defects in the distal segment of the inferior vena cava, arteriovenous fistula involving the left internal iliac artery and peri‑uterine veins as well as presence of a 7 cm diameter uterine fibroid associated with multi­ple subserosal smaller uterine nodules. Biopsy of the largest uterine fibroid revealed proliferation of smooth muscle cells, suggestive for a leiomyoma.
The patient was referred to cardiac surgery for removal of the cardiac mass. Surgically, the intracardiac mass was confirmed to extend from the inferior vena cava and had to be resected at this level. Macroscopic examination revealed a ring-shaped mass of 4 cm diameter, of grey colour and elastic consistency with a central pinhole, while microscopic examination showed the right intracardiac mass to be an old ring-shaped thrombus, composed of fibrin, red blood cells, platelets, leukocytes, with central neovascularization vessels (Fig. 1B,C).
The differential diagnosis of the highly mobile ring-shaped intracardiac mass included intravenous leiomyomatosis originating from previously documented uterine fibroid [1] as well as an intracardiac thrombus associated with vascular malformation of the peri‑uterine veins [2]. The macroscopic aspect and consistency were suggestive for cardiac leiomyomatosis rather than a thrombus, but microscopic exami­nation confirmed the diagnosis [3]. Also, differential diagnosis included right atrial myxoma, a rare and benign tumour, presenting as a sessile, pedunculated cardiac mass, isoechoic with definite margins and with smooth, sometimes friable and gelatinous-like macroscopic appearance and a particular microscopic appearance [4]. A giant Eustachian valve may also mimic a thrombus but appear as a rigid, elongated structure or as a membranous, undulating, echogenic mass [5].
The patient was discharged in good condition, was medically treated to prevent pulmonary embolism and to control her blood pressure and was scheduled for hysterectomy.
This case is suggestive for the very rare and unusual presentation of a life-threatening, ring-shaped intracardiac thrombus and emphasizes the limitations of the non-invasive diagnostic techniques used to differentiate the aetiology of intracardiac masses with unusual shape and associated with particular clinical situations, requiring surgical removal and pathological examination to confirm the diagnosis.
The author declares no conflict of interest.

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