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pituitary_macroadenoma

Pituitary macroadenoma

Pituitary adenoma greater than 10 mm in size and are approximately twice as common as pituitary microadenomas.

Pituitary macrocadenomas are the most common suprasellar mass in adults, and responsible for the majority of transsphenoidal hypophysectomies.

see Nonfunctioning pituitary macroadenoma.

Clinical features

Headache possible due to elevated intrasellar pressure.

Biomarkers

Biomarkers of aggressive behavior have been identified in the pathology literature, including the proliferative marker MIB1. In the radiology literature, diffusion weighted imaging and low ADC values provide similar markers of aggressive behavior in brain tumors.

Tamrazi et al., determine a strong correlation of low ADCvalues and MIB-1, demonstrating the potential of diffusion imaging as a possible biomarker for atypical, proliferative adenomas, which may ultimately affect the surgical approach and postoperative management 1).

Diagnosis

Compared with pre-contrast T1-weighted images only, post-contrast images provided considerable additional information, but not infrequently this information could also be extracted from pre-contrast T2-weighted images. Post-contrast images were superior regarding the tumour relationship to the cavernous sinus and to the normal pituitary tissue. T2-weighted images were helpful in the diagnosis of degenerative changes, in particular intratumoural haemorrhage. A positive correlation was found between the T2 value (from dual echo sequences) and the degree of enhancement in areas with an appearance of solid tumour tissue, and the enhancement was significantly lower in GH secreting pituitary adenoma than in non-secreting ones. It is concluded that the use of Gd-DTPA is often justified in pituitary macroadenomas, particularly in pre-operative evaluation 2).

Treatment

The goal of treatment is complete cure. When this is not attainable, reducing tumor mass, restoring hormone function, and restoring normal vision are attempted using medications, surgery, and radiation. Pituitary macroadenomas often require surgical intervention for cure. The exceptions to this rule are the macroprolactinomas, which usually have an excellent response to medical therapy. The tumor size may be diminished but often does not disappear completely. Medical treatment can play a role in reducing tumor size, controlling hormonal excess, or correcting hormonal deficiency.

see Pituitary macroadenoma surgery.

Case series

1)
Tamrazi B, Pekmezci M, Aboian M, Tihan T, Glastonbury CM. Apparent diffusion coefficient and pituitary macroadenomas: pre-operative assessment of tumor atypia. Pituitary. 2016 Oct 12. PubMed PMID: 27734275.
2)
Lundin P, Bergström K. Gd-DTPA-enhanced MR imaging of pituitary macroadenomas. Acta Radiol. 1992 Jul;33(4):323-32. PubMed PMID: 1633042.
pituitary_macroadenoma.txt · Last modified: 2018/10/01 08:35 by administrador