Masson’s tumors or intravascular papillary endothelial hyperplasia (IPEH) are rare nonneoplastic vascular lesions, uncommon in the central nervous system. In fact, there has been selected intracranial reported cases. Their pathogenesis remains unclear. They have been found case report of IPEH found in the larynx, cervical and thyroid region, scalp, central canal, posterior fossa, internal auditory canal, urinary bladder, etc (please refer to References for related case examples).

Viewed as a mimicker of meningiomas, Masson's tumors should be considered among enhancing intracranial vascular lesions. Resection is often curative though recurrence can happen with subtotal resection. 

Fortunately, almost 3 years post-resection, our patient remains free of tumor recurrence.  

In consideration of the rarity of this tumor, we provide this case to the Radiopedia community for help with pre-operative radiological diagnosis.

The key imaging features match those expressed on the related Radiopedia article. DWI-ADC sequences were not performed. As per literature, Masson's tumors would show mixed areas of restricted diffusion, likely owing to hyperplastic endothelial cell proliferation inducing low-ADC values versus capillary channels and hemorrhagic contents inducing no DWI restriction, which would be consistent with findings on the pathology report. The absence of cytologic features of malignancy (no necrosis nor mitosis) with the presence of CD31 staining have also been reported.

Courtesy of Profs. Rosenbloom L. and Levental M., exemplary teachers and respected radiologists.