A Rare Case of Intravascular Papillary Endothelial Hyperplasia of the Hypopharynx: A Case Report and Literature Review.

Intravascular papillary endothelial hyperplasia (IPEH), also known as Masson's hemangioma, is a rare benign vascular lesion characterized by an unusual pattern of endothelial proliferation within a thrombosed vessel. Histologically, IPEH is defined by prominent intraluminal papillary structures composed of a single layer of enlarged endothelial cells, lacking cytologic atypia, mitotic activity, and necrosis. Here, we report a rare case of IPEH identified in the hypopharynx of a 56-year-old male patient, incidentally, on imaging for evaluation of unrelated upper back pain. We describe the clinical presentation, histopathologic findings, differential diagnosis, and review of the current literature to enhance recognition and management of this entity in rare/unusual sites.