Carcinomatous encephalitis: CT and MR findings.

Intracranial metastases from carcinoma are common , occurring in up to 24% of cancer patients at autopsy [1]. Typically, intracranial metastatic disease is characterized by multiple intracerebral mass lesions near the gray-white junction with surrounding edema. Diffuse involvement of the brain without dominant mass lesions may occur with leptomeningeal spread of primary brain tumors, Iymphoproliferative malignancies, and carcinomas [2]. Another form of diffuse neoplastic involvement of the brain is the rare carcinomatous encephalitis. This term was initially used by Madow and Alpers in 1951 [3] to describe the diffuse spread of carcinoma cells to the brain parenchyma and meninges without formation of macroscopic masses. To our knowledge, this entity has not been reported in the radiology literature. We present the case of a 60-year-old woman with clinical features of subacute encephalopathy and hemiparesis. CT and MR imaging revealed innumerable tiny nodules scattered throughout the gray and-white matter of the brain, corresponding to nodules of papillary adenocarcinoma found at brain biopsy.