PRL and neoplasm: The tumor now known as the poorly-differentiated Pit1-lineage tumor, previously known as “silent subtype 3 adenoma”, is a neoplasm composed of poorly-differentiated, polygonal to spindle-shaped chromophobic cells that express Pit1 as well as focally ER and GATA3, and can produce different combinations of GH, prolactin, α-subunit and/or TSH [49,56] (Figure 6).