Intravascular Papillary Endothelial Hyperplasia Occurring Within the Thyroid Gland: A Rare Event

Intravascular papillary endothelial hyperplasia or Masson tumor is a rare tumor. It is a benign vascular lesion that is simply an unusual form of an organizing thrombus. Its primary importance lies in that it may be mistaken for an aggressive lesion because it has a nonspecific imaging appearance. We discuss a case of intravascular papillary endothelial hyperplasia that occurred in the thyroid gland, provide clinical and pathologic correlation, and include a brief review of the literature.