Co-secretion of hormones was observed at diagnosis in eight patients, PRL/GH (n = 4), thyroid-stimulating hormone (TSH)/growth hormone (GH) (1), TSH/follicle-stimulating hormone (FSH), (TSH-driven hyperthyroidism and enlarging testes; lineage transcription factor steroidogenic factor 1 (SF-1) was positive, pituitary-specific positive transcription factor 1 (Pit-1) and TSH immunohistochemistry were not investigated) (1), FSH/luteinizing hormone (LH) (n = 1), and PRL/glycoprotein α-subunit (8.8, ref <0.7 IU/L) (n = 1). Here, POU1F1 is linked to hyperthyroidism.