] Epilepsy 1993;6:112-114 © 1993 Butterworth-Heinemann

Astrocytoma Infiltrating Cerebral Cortex Causing Epileptic Seizures: A Pictorial Essay

John J. Kepes and 1'2Barbara R. Fegley

Infiltration of the cerebral cortex by gliomas often leads to epileptic seizures. This is due partly to mass effect and possibly to focal ischemia because of compression of capillaries. Compression and "strangulation" of individual cortical neurons by neoplastic glial cells (in this case astrocytes) is probably also an important factor in the genesis of seizures. This essay depicts the light and scanning electron micro- scopic features of neoplastic astrocytes surrounding and compressing individual neurons of the cortex in a patient with epilepsy. Key Words: Astrocytoma--Cor- tical neurons--Epilepsy.

Epileptic seizures are often the result of irritation or distress of living neurons. The cause of such distress may be chemical, metabolic, or mechanical. Seizures are a wel l -known and fairly com m on symptom of neoplastic involvement of the cerebral cortex. They can come about as a result of external compress ion (such pressure usually has the additional effect of compress ing the capillary bed, thereby adding an ischemic componen t to the mechanical irritation). In- filtrative gliomas may create "crowding" within the cortex, another generally accepted source for neu- ronal distress. The following illustrations are f rom a case in which the actual "strangling" of individual cor- tical neurons by the cell processes of infiltrating astro-

cytes could be observed, and this was the likely cause for the "cries of anguish" from the affected neurons that were translated into epileptic seizures.

The patient was a 50-year-old physician, previously of good health, whose first signs of neurological dis- ease were a series of seizures with a left frontal focus. Scans showed a superficially located mass in that area, the patient underwent surgery, and a fairly well- delineated tumor was found involving the cortex and underlying white matter. Microscopically, a mixed gemistocytic and fibrillary astrocytoma was found to infiltrate the cortex. After resection of the involved area the patient 's seizures stopped. Figures 1 and 2 are from the surgical specimen.

Received November 19, 1992; accepted November 24, 1992.

From the Departments of Pathology and lNeurosurgery and 2Anatomy, University of Kansas College of Health Sci- ences and Hospital, Kansas City, KS, U.S.A.

Address correspondence and reprint requests to Dr. J. J. Kepes at Department of Pathology and Oncology, Univer- sity of Kansas Medical Center, 39th and Rainbow Boule- vard, Kansas City, KS 66103, U.S.A.

112 J EPILEPSY, VOL. 6, NO. 2, 1993

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Figure 1. A: Diffuse infiltration of cortex by moderately differentiated fibrillary and gemistocytic astrocytoma. Hematoxylin-eosin stain, ×80. B-D: Compression and "strangling" of otherwise apparently viable neurons by astrocytic cell bodies and processes. Hematoxylin-eosin stain, >(350. E and F: Same areas as in A-D with combined immunoperoxidase stain for glial fibrillary acidic protein and 1°/o thionin (Nissl stain). The cytoplasm of astrocytes stains brown, the perikarya of neurons blue. ×350.

j. j. KEPES AND B. tL FEGLEY

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Figure 2. Scanning electron micrographs show cut surface of a cortical neuron in center (,4) and in left lower comber (B). The "spongy'" appearance of the perikaryon reflects endoplasmic reticulum and mitochondria. The neuronal cell membrane is surrounded by octopus-like "tentacles" (astrocytic cell processes) A: ×4,000. B: >(10,000.

114 J EPILEPSY, VOL. 6, NO. 2, 1993