LAUSR

A 37-year old female patient with a history of subtotal hysterectomy for endometrioma presented with a 6-month history of abdominal discomfort. There was a palpable pelvic mass, facial swelling, and prominent neck veins. Abdominal computer tomography (CT) scanning revealed pelvic tissue masses extending into ovarian and renal veins, inferior vena cava (IVC), and heart. A right atrial (RA) mass (6.6 3.6 cm) arising from a dilated IVC and extending into the right ventricle (RV) was demonstrated by echocardiography (ECHO). (Panels A/B, Supplementary material online, Videos 3-5) Cardiac magnetic resonance (CMR) cine imaging demonstrated the diastolic movement of the mass towards the RV resulting in intermittent RV inflow obstruction (Panel C, Supplementary material online, Videos 1-2) and the intravascular origin of the tumour. (Panel D, Supplementary material online, Video 1) Histopathology confirmed leiomyomatosis. There were desmin-positive spindle shaped cells without nuclear atypia nor necrosis. CD 117 was negative and Ki-67 index less than 5%. Intravascular leiomyomatosis is the nontissue-invasive spread of benign fibroma cells from its origin (almost always uterine leiomyomata) via the uterine veins and IVC to the right heart. The condition is very rare with about 200 reported cases. Patients tend to be asymptomatic until the tumour reaches the heart. The majority of patients present with signs and symptoms of heart failure. Few patients exhibit symptoms caused by the primary tumour-like abdominal pain or menorrhagia. The most feared complication is the sudden obstruction of the RV outflow tract. Operative resection is the primary treatment. Recurrence rates appear to be low. Intravascular leiomyomatosis should be considered in females presenting with symptoms of heart failure or venous obstruction. (Panel A) ECHO. Apical four chamber view. Large mass in RA extending into RV. (Panel B) ECHO. Subcostal view. IVC completely filled with tumour mass (*) that extends into the RA (#). (Panel C) CMR. Axial FIESTA cine. Homogenous mass in the RA measuring 7.2 3.3 cm. (Panel D) CMR. Axial FIESTA cine. Tumour mass within IVC (*).