Palliative Debulking of an Aortic Body Tumour With Right Atrial Invasion in a Dog Under Partial Cardiopulmonary Bypass

Figures

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  FIGURE 1. Echocardiographic and abdominal ultrasonographic findings at initial presentation. (A) Right parasternal long‐axis four‐chamber view showing marked right atrial enlargement and a large intracavitary mass adjacent to the interatrial septum. The mass was heterogeneously echogenic. (B) Right parasternal short‐axis view at the heart base demonstrating that the mass appeared to originate from the heart base region adjacent to the aorta; the maximal dimensions were 3.2 × 3.1 cm. (C) Continuous‐wave Doppler recording of tricuspid regurgitation obtained from a left parasternal long‐axis view. The peak tricuspid regurgitant velocity was 4.03 m/s (estimated pressure gradient, 64.9 mmHg). (D) Abdominal ultrasonography showing a large volume of anechoic free fluid cranial to the urinary bladder (ascites). Abbreviations: Ao, aorta; LA, left atrium; LV, left ventricle; RA, right atrium.

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  FIGURE 2. Intraoperative findings during debulking of the right atrial mass under partial cardiopulmonary bypass. (A) Intraoperative view immediately after right atriotomy showing that the mass occupied most of the right atrial lumen. (B) The intracavitary component of the mass was gently stabilised with Babcock forceps to improve exposure and was carefully debulked; excessive traction was avoided because the mass was firmly adherent to the septal aspect of the right atrium. (C) After debulking, blood flow from the caudal vena cava into the right atrium appeared improved, and the right atrial lumen refilled with blood. (D) The right atrium was closed in two layers with a simple continuous pattern after limited palliative debulking. The residual tumour was intentionally left at the firmly adherent portion to avoid rupture, perforation, or uncontrollable haemorrhage. Visible labels indicate the mass, right atrial wall, right atrial lumen, Babcock forceps, and suture line. Abbreviation: RA, right atrium.

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  FIGURE 3. Postoperative echocardiographic findings. (A) Right parasternal long‐axis four‐chamber view on Day 14 showing that the intracavitary mass was no longer clearly visible. (B) Right parasternal short‐axis view at the heart base on Day 14. Similar to panel A, the mass was not clearly identified. (C) Right parasternal long‐axis four‐chamber view on Day 360 showing a documented recurrent mass adjacent to the interatrial septum. (D) Measurement of the recurrent mass, with maximal dimensions of 2.0 × 1.9 cm.

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  FIGURE 4. Gross and histopathological findings at necropsy. (A) Gross cross‐sectional image of the heart at necropsy showing the heart base tumour extending into the right atrium. The cardiac base and apex are indicated for orientation. (B) Cut surface of the left caudal lung lobe showing an intraluminal lesion within a pulmonary artery, consistent with thrombus/tumour embolus, and metastatic foci. (C) Histopathology of the cardiac mass: neoplastic cells resembling chemoreceptor cells proliferating in small‐ to medium‐sized nests separated by fibrovascular stroma (zellballen pattern) with areas of solid, sheet‐like growth (haematoxylin and eosin [H&E] stain; objective × 40). (D) At the cranial aspect of the left ventricular wall, the tumour infiltrated the myocardium (H&E stain; objective × 40). Abbreviations: LA, left atrium; LV, left ventricle; RA, right atrium.