Figure 16. Densely Granulated Somatotroph Adenomas are composed of acidophilic cells arranged in a trabecular, sinusoidal, or diffuse architecture (a). The tumor cells show diffuse cytoplasmic immunoreactivity for GH (b) and strong nuclear immunoreactivity for Pit-1 (c). In contrast to the sparsely granulated variant (see keratin positivity is perinuclear and faint (d) .