Pineal parenchymal tumour of intermediate differentiation

Case contributed by A.Prof Frank Gaillard

Presentation

Headache.

Patient Data

Age: 60 years
Gender: Female

An ovoid lesion is located in the pineal region appearing below the internal cerebral veins and separate form the splenium. It has calcifications peripherally posteriorly. It is slightly hyperdense to adjacent midbrain but is inseperable from the tectum. No oedema. 

A pineal region mass demonstrates heterogeneous contrast enhancement and intermediate T2 signal. Diffusion weighted imaging demonstrates reduced ADC values (approximately 600 x 10-6 mm2/s) suggesting high cellularity. It is definitely separate from the tectum which it distorts and compresses without complete obliteration of the aqueduct. Attenuated flow void is seen in the aqueduct, and although no overt obstructive hydrocephalus is yet present, there is some distension of the recesses of the third ventricle. 

Review of prior CT demonstrates the calcification of the pineal gland to be located peripherally around the mass, rather than engulfed. The remainder of the brain is unremarkable in appearance.

Conclusion:

Appearances most likely represents a pineal parenchymal tumour, with high cellularity worrisome for a higher grade despite the well-circumscribed appearance (pineal parenchymal tumour of intermediate differentiation (WHO II or III). Pattern of displacement of calcium, gender, and low ADC values make a germ cell tumour less likely.

Case Discussion

The patient went on to have a resection. 

Histology

MICROSCOPIC DESCRIPTION:

Sections show a moderately cellular tumour demonstrating focal rosette formation and solid sheet-like growth. Tumour cells contain scant cytoplasm, oval granular nuclei and inconspicuous nucleoli. No mitoses, necrosis or microvascular proliferation are seen.

Immunohistochemical results show tumour cells stain: GFAP-, CD117-, Chromogranin- and Synaptophysin+. The Topoisomerase proliferation index is approximately 1-2%.

FINAL DIAGNOSIS: Pineal parenchymal tumour with intermediate differentiation (WHO II).

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Case information

rID: 58133
Published: 3rd Feb 2018
Last edited: 16th Jul 2018
Inclusion in quiz mode: Included

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