Diffuse subependymal periventricular metastases. Report of three cases.

Three clinicopathologic cases with a remarkable pattern of extensive diffuse subependymal periventricular spread of cerebral metastases from solid systemic cancer are reported. Two patients had a small cell carcinoma of the lung. In the third case, the histologic features of the brain metastases were consistent with a neuron-specific enolase-positive, small cell anaplastic carcinoma. Involvement of the choroid plexus and leptomeninges was moderate or absent. Intraparenchymatous nodular metastases were not found except in one case in which rare nodular superficial cortical metastases were present. The clinical data were nonspecific except for orthostatic hypotension, in one patient, which was probably due to the infiltration of the floor of the third and fourth ventricles. Results of the cerebrospinal fluid examination, available in two cases, were normal. The only diagnostic investigation was contrast-enhanced computed tomography scanning.