Pituitary macroadenoma invading base of skull

Case contributed by A.Prof Frank Gaillard

Presentation

Right eye symptoms and abnormal pituitary function tests.

Patient Data

Age: 50 years
Gender: Female

A large sellar and suprasellar mass is identified with invasion of the right cavernous sinus, the sphenoid body and sinuses, in particular the right. Lysis of the right petrous apex, suggestive of invasion. Posterior and anteromedial dehiscence of the right carotid canal is noted.The ventricular size is within normal limits.

MRI

MRI brain

A large avidly enhancing sellar/parasellar and suprasellar mass is evident. It measures 3.9 x 3.8 x 3.1 cm. The lesion invades the sphenoid bone, filling most of the right sphenoid sinus but also involving the left. It also invades into the base of the pterygoid

process on the right and into the adjacent apex of the petrous temporal bone. Posteriorly it invades through the right side of the clivus into the prepontine cistern. High T1 signal material within the remaining sphenoid sinus may represent proteinaceous or haemorrhagic fluid. 

The lesion is intimately related to the right ICA, from the posterior genu of the cavernous ICA, enveloping it in the cavernous sinus (and invading the cavernous sinus) and closely related to the supraclinoid ICA to just before the bifurcation. Enhancement is still noted within the internal carotid artery. 

In the suprasellar region it abuts and deforms the optic chiasm and adjacentoptic nerves. A further superior projection which is high T1 signal intrinsically (?haemorrhage) passes in the vicinity of the right oculomotor nerve, close to the cavernous sinus, and may impinge it. Anteriorly the lesion reaches close to the orbital apex.

Fluoroscopy

Intra-operative image intensifier

.

Histology

The sections show fragments of a moderately hypercellular adenoma. Tumour cells have uniform round and oval vesicular and hyperchromatic nuclei and a variable amount of pale cytoplasm which are arranged in trabeculae and diffuse sheets intersected by thin-walled capillaries. No mitotic figures or areas of necrosis are seen and there is no included normal anterior pituitary tissue.

Immunohistochemistry shows strong perinuclear staining for CAM5.2 in the majority of tumour cells. No immunostaining for growth hormone, prolactin, ACTH, FSH, LH, TSH, S-100 protein, GFAP or oestrogen receptor (ER) is seen in tumour cells. The features are of null cell adenoma. The topoisomerase labelling index is <1%.

FINAL DIAGNOSIS: Pituitary tumour:   Null cell adenoma

Case Discussion

This case demonstrates how pituitary macroadenomas can extend extensively into the base of skull with only modest supratentorial extension. 

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Case information

rID: 17612
Case created: 30th Apr 2012
Last edited: 6th Nov 2015
Inclusion in quiz mode: Included

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