# Pathogenesis of Cardiac Valvular Hemangiomas: A Case Report and Literature Review

## TL;DR

This case report describes a rare tricuspid valve hemangioma in an infant and discusses its possible origin involving endothelial and mesenchymal cell transitions.

## Contribution

The first reported case of a tricuspid arteriovenous hemangioma and evidence of endothelial-mesenchymal transitions in its development.

## Key findings

- The hemangioma was localized on the tricuspid valve and diagnosed as arteriovenous in nature.
- Endothelial cells showed positivity for SMA, suggesting endothelial-to-mesenchymal and mesenchymal-to-endothelial transitions.
- No tumor recurrence or complications were observed after surgical removal.

## Abstract

Valvular hemangiomas are uncommon vascular anomalies that appear on the surface of heart valves. They can cause an array of non-specific symptoms and are consequently rarely diagnosed, with only 31 such cases (including the present one) reported to date in the literature; the present case is the first report of an arteriovenous hemangioma with a tricuspid localization. During the preoperative echocardiographic examination for a ventricular septal defect, a mass was incidentally discovered on the tricuspid valve of a 9-month-old infant. The involved leaflet was surgically removed and sent to the pathology department for analysis and subsequently diagnosed as an arteriovenous hemangioma. The patient recovered well, with no local tumor recurrence or other complications. The microscopic examination showed multiple blood vessels which stained positive for the endothelial markers CD31 and CD34 and which did not express D2-40, normally found in lymphatic endothelia. Surprisingly, endothelial cells lining the vessels also showed positivity for SMA, a mesenchymal cell marker, indicating a possible involvement of endothelial-to-mesenchymal transition and its opposite process, mesenchymal-to-endothelial transition, in the pathogenesis of these vascular anomalies.