Focal cerebral infarctions associated with perivascular tumor infiltrates in carcinomatous leptomeningeal metastases.

Diffuse carcinomatous leptomeningeal metastases "carcinomatous meningitis") have the usual clinical course involving multifocal nerve root deficits and a variable diffuse encephalopathy. In contrast, we describe a patient with carcinomatous leptomeningeal metastases who presented with clinical signs of meningitis and focal cerebral infarction. Over an 8-month period, multiple cerebral infarctions and cranial neuropathies developed. Postmortem examination of the patient's brain revealed diffuse leptomeningeal infiltration by a signet-ring adenocarcinoma. The extensive involvement of the subarachnoid space with tumor was associated with dense neoplastic infiltration of the Virchow-Robin spaces. These perivascular tumor infiltrates were accompanied by multifocal mural invasion and, less frequently, by intravascular tumor cells obliterating the lumen. Focal hemorrhagic infarcts in the cerebral cortex corresponded to areas of microscopic vasculopathy. This case provides evidence that tumor-associated vasculopathy with resultant ischemia plays a role in the pathogenesis of focal cerebral infarctions in carcinomatous leptomeningeal metastases.