MR imaging findings in a dog with intravascular lymphoma in the brain

Intravascular lymphoma (malignant angioendotheliomatosis, angiotrophic lymp homa) is a rare neoplastic disorder in dogs. The literature contains few re ports in dogs and a single report in a cat. Intravascular lymphoma is chara cterized by an intravascular proliferation of malignant lymphocytes. This u nique angiocentric distribution of neoplastic cells leads to the characteri stic clinicopathologic feature of thromboses and infarctions. In people, in travascular lymphoma has a predilection for vessels in the central nervous system (CNS) and skin. Typically, affected patients have episodic symptoms that coincide with the timing of infarctions. This report details the clini copathologic description and magnetic resonance (MR) images of a dog with i ntravascular lymphoma that resulted in multiple CNS infarctions. Abnormalit ies identified with MR imaging consisted of multifocal hyperintensities obs erved in pre-contrast T1-weighted, T2-weighted, intermediate-weighted, and FLAIR pulse sequences. Lesions were most conspicuous on the FLAIR images. I n addition, there was mild enhancement of the lesions seen in post-contrast T1 weighted images.