GH1 and adenoma: If compared to densely granulated (DS) GH-secreting PitNETs, sparsely granulated (SG) tumors are more likely to invade the cavernous sinus (grades 3–4 of Knosp’s classification) (17).Some MRI sequences and techniques may help to predict the more SG phenotype of GH secreting PitNET: high T2 signal intensity, due to a low collagen content and low number of secreted granules, and a more avid enhancement are found in SG adenomas (17).