Specific Imaging Findings

Meningeal carcinomatosis on MR imaging presents as a focal or multifocal, frequently diffuse linear and/or nodular contrast enhancement along the leptomeninges – covering the surface of the brain: within the cortical sulci and the cerebellar folia, along the brainstem and cranial nerves. FLAIR images can show increased signal of the subarachnoid spaces, within the sulci, as well as hyperintense signal of edema in the adjacent brain. T2WI and unenhanced T1WI are usually unremarkable, unless vasogenic edema is present in the adjacent brain, either from advanced infiltrative disease, or from concurrent intra-axial lesions. Unenhanced CT is usually normal, while contrast-enhanced CT is positive usually only with advanced disease. The posterior fossa is a preferred site of involvement and spinal imaging often reveals spread of the disease along the entire neuraxis. Association with dural and intra-axial brain metastasis is commonly encountered. Perfusion imaging shows increased cerebral blood volume in larger lesions.

Pertinent Clinical Information

Leptomeningeal carcinomatosis most often presents late in the course of neoplastic disease, and carries a particularly dismal prognosis, especially if associated with solid tumors. The hallmark of clinical presentation is a cancer patient who complains of a focal neurologic dysfunction and is found to have multifocal signs on neurologic examination, commonly including a single or multiple cranial nerve dysfunction. The clinical course is relentlessly progressive; treatment is limited and cures are the subject of case reports.