previous in index  ·  next in index 
 
 
 
Neuroradiology

Macroadenoma, pituitary

pituitary tumour of more than 10 mm in diameter. A macroadenoma can remain confined within the sella turcica, or it may grow upward, downward, laterally or more commonly in all directions. When growing upward the tumour will compress the optic chiasm and produce bitemporal hemianopia. Laterally the tumour may compress or invade the cavernous sinuses with involvement of the cranial nerves and diplopia.

From an endocrinological point of view macroadenomas may be nonsecreting or secreting. The most common secreting macroadenoma is the prolactinoma, followed by GH secreting adenomas.

Radiologically, plain films usually show an expanded sella with erosion and depression of the sellar floor toward the sphenoid sinus.

CT shows the same bony changes and the mass lesion, usually isointense, with marked enhancement.

MRI (Fig.1) better shows involvement of the surrounding structures with elevation of the chiasm, compression and invasion of the cavernous sinuses and encasement of the carotid siphon. The tumour is usually isointense on T1-weighted images and shows marked enhancement following gadolinium injection. Sometimes haemorrhagic and cystic components are present. Also, see pituitary adenoma, intrasellar mass and microadenoma pituitary.

GS

To view high resolution images,
please register first.

Click  here to register.

Already registered? Enter your e-mail in the window below.
Re-register

Fig.1

a. T1-weighted image, axial MR without contrast. Isointense space-occupying lesion originating from the sella turcica and extending bilaterally, mainly on the right side. The cavernous sinus is invaded on the right side, with encasement of the internal carotid artery without narrowing. b. Axial, T1-weighted MR image, following gadolinium injection of contrast. Marked homogeneus enhancement of the tumour. c, d. Axial, coronal and sagittal T1-weighted MR images, following gadolinium injection of contrast. Marked homogeneous enhancement of the tumour. The superior suprasellar, inferior sphenoidal and lateral cavernous extension of the tumour is well seen. The sella turcica is markedly enlarged, the floor is depressed, the chiasm is compressed and elevated.
Macroadenoma, pituitary, Fig.1 (a)
Macroadenoma, pituitary, Fig.1 (b)
Macroadenoma, pituitary, Fig.1 (c)
Macroadenoma, pituitary, Fig.1 (d)