Metastatic colon cancer presenting as pituitary mass.

it is not possible to differentiate PM from pituitary ade-noma solely on the basis of radiographic appearance. However, certain characteristics have been described more commonly in PM, including (1) a computed tomographic (CT) scan revealing a sellar mass causing erosion of the sellar floor without causing sellar enlargement; (2) magnetic resonance imaging (MRI) findings of a dumbbell-shaped sellar mass with a clear margin at the diaphragm level, best seen on a sagittal image, 17 , 18 and loss of-high intensity signals of the posterior pituitary in T1 weighed images; (3) angiog-raphy (if done), typically revealing significant tumor staining reflect-ing high vascularity. 19 None of these radiologic findings are suffi-ciently specific for PM; similar patterns may be present in primary pituitary tumors.