Plurihormonal poorly differentiated Pit-1 positive tumors (previously designated as “silent subtype 3 adenoma”) are rare tumors composed of large polygonal or spindle shaped cells, with atypical nuclei, sometimes containing inclusions, so called nuclear spheridia that can be observed on routine HE stains or, more readily, on electron microscopy [29, 66–68]. This evidence concerns the gene POU1F1 and adenoma.