Unexpected Huge Prevalence of Intracardiac Extension of Wilms Tumor-A Single Center Experience from a Ugandan Hospital

Abstract

Wilms tumor (WT) is the most common primary renal malignancy in young children. WT vascular extension to the inferior vena cava (IVC) occurs in 4-10% of cases and can reach the right atrium (RA) in 1%. Data on WT clinical presentation and outcome in developing countries are limited. The aim of the present study is to describe the prevalence of intracardiac extension in a consecutive population of WT patients observed in a large non-profit Ugandan hospital. A total of 16 patients with a histological diagnosis of 29 WT were screened in a 6-month period. Patient n°2, a 3 y/o child, presented with a 3-week history of abdominal distension, difficulty in breathing, and swelling of the lower limbs. A cardiovascular system exam showed rhythmic heart sounds, a heart rate of 110 beats per minute, and a pansystolic murmur on the tricuspid area; the abdomen was grossly distended with a palpable mass in the right flank, hepatomegaly, and splenomegaly. An abdomen ultrasound showed an intra-abdominal tumor, involving the right kidney and the liver and extended to the IVC. An ultrasound guided biopsy showed a picture consistent with WT. Cardiac echo showed a huge, mobile, cardiac mass attached to the right side of the interatrial septum, involving the tricuspid valve annulus, causing a "functional" tricuspid stenosis. The patient died of cardiogenic shock 7 days after admission. Patient n°3, a 3 y/o child, presented with analogue symptoms and the same diagnosis. The cardiac echo showed a round mass in the RA. Thirteen more patients were screened with cardiac echo, showing a normal heart picture. In our limited series, we found WT cardiac extension in three patients over 16 (19%). Cardiac echo performed routinely can lead to a better staging, prognostic, and therapeutic assessment. In our setting, the intra-cardiac extension could be more frequent than previously reported and might have prognostic implications.

Keywords: Wilms tumor; echocardiography; heart diseases in sub-Saharan Africa.

Figure 1

Case 1 echocardiographic images. Apical 4 chambers view: a gross ovoid mass measuring 5.7 × 2.3 cm can be visualized in the RA. The mass engages the TV plane protruding into the right ventricle (Panel (A)). Subcostal view (Panel (B)) confirms the pres-ence of a very mobile mass and shows a mild-moderate associated pericardial effusion (white arrow). The mass has an irregular and inhomogeneous structure with ultrasound images consistent with areas of vacuolization and/or tissue necrosis (white arrow) (Panel (C)).

Figure 2

Case 1 echocardiographic images. Color Doppler image (Panel (A)) shows a significant acceleration of diastolic flow at the level of the TV plane, almost entirely occupied by the mass. Panel (B) shows the CW Doppler trace which confirmed a severe TV stenosis. Abbreviations: TV: Tricuspid Valve; CW: Continuous wave.

Figure 3

Case 2 echocardiographic images. Apical 4 chambers view: a 3.0 × 2.5 cm rounded mass is clearly seen inside the RA. Compared to the other case, the mass has limited motion with poor systolic-diastolic excursion (Panel (A,B)), remaining away from the plane of the TV. Abbreviations: RA: Right atrium; TV: Tricuspid Valve.