Intravascular Papillary Endothelial Hyperplasia (Masson Tumor) of the Right Thumb: A Case Report and Literature Review.

The Masson tumor is a benign vascular tumor named after Pierre Masson, the French pathologist who originally described it in 1923, terming it "hémangio-endothéliome végétant intravasculaire." It is a rare tumor that can arise in any area throughout the body. However, the exact cause of Masson tumor remains poorly understood, and its diagnosis is challenging and difficult to distinguish from several other soft-tissue tumors. In this report, we report a case of Masson tumor arising in the right thumb that is only the second reported case in the hand in Saudi Arabia.