Astrocytoma of the septum pellucidum

Case contributed by Frank Gaillard


Intermittent headaches.

Patient Data

Age: 50 years
Gender: Female

CT brain


A nodule is located at the foramen of Monro which is well-defined and homogeneously isodense to brain and has a maximal diameter of 1.2 cm measured. There is no evidence of acute hemorrhage or calcification within this lesion. No enhancement. Asymmetry of the lateral ventricles is within normal limits. There is no evidence of uncal or tonsillar herniation. 

MRI brain


A 1.1 x 1.3 cm well-defined lesion closely related to the septum pellucidum and right foramen of Munro  demonstrates mild hyperintensity on FLAIR weighted images and his isointense on T1 weighted images. No discernible enhancement. The ventricles demonstrate mild prominence of the occipital horns however the remainder of the lateral ventricles, third and fourth ventricles are within normal limits. No other focal lesions are identified. Vascular flow voids are preserved.

This patient went on to have a trans-callosal resection.


MICROSCOPIC APPEARANCE: The sections show a moderately cellular astrocytic tumor. There are scattered neoplastic astrocytes, with mildly enlarged, hyperchromatic and elongated nuclei. They present as bare nuclei with inconspicuous cytoplasm. No mitoses are seen. There is no evidence of endothelial cell hyperplasia or necrosis. The tumor cells are GFAP positive. The Ki-67 index is 1%. The features are those of diffuse astrocytoma.

FINAL DIAGNOSIS: Right lateral ventricle: Diffuse astrocytoma (WHO Grade II).

Case Discussion

This case illustrates a rare tumor - an astrocytoma arising from the septum pellucidum.

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