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Findings: A hypointense signal lesion measuring 4 x 6 x 4 mm in the AP, transverse and longitudinal dimensions respectively is located at the posterior inferior slightly right of mid line in the pituitary gland. The optic chiasm and pituitary stalk appear structurally intact.
Diagnosis: Microadenoma of the pituitary gland.
Discussion: Microadenoma of the pituitary gland usually appears hypointense on T1 weighted images and has a variable appearance on the T2 weighted images. Dynamic images of the sella are obtained following the administration of Gadolinium to further delineate the size of the lesion and the extent of involvement into the cavernous sinus.
A microadenoma, by definition, measures less than 1 cm. 75% of these lesions cause hormonal abnormalities whereas as the nonhormonally active lesions become symptomatic secondary to the size. Clinical symptoms associated with pituitary adenomas can be visual disturbance and headaches. Pituitary adenomas can produce a spectrum of hormonal abnormalities. Prolactin producing adenomas are the most common, however, but growth hormone, ACGH, and gonadotrophic producing adenomas are also possible.
References:
Grossman RI, Yoursen DM. Neuroradiology, the Requisites.
Mosby, St. Louis; 1994:313-315.
Cotran RS, Kumar, Robbin SL. Robbin's Pathologic Basis of Disease,
5th Edition. W. B. Saunders, Co., Philadelphia; 1994:1116-1118.
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