Densely-granulated somatotroph tumors, found in 30–50% of acromegaly patients, are composed of deeply eosinophilic tumor cells (Figure 1), with a diffuse positivity for GH and a perinuclear staining pattern of low molecular weight keratins, that closely resemble normal somatotrophs [12,13,14]. Here, GH1 is linked to neoplasm.