Prolactin presents in all pituitary tumors of acromegalic patients

Plurihormonal pituitary adenomas: immunostaining of all pituitary hormones is mandatory for correct classification

“…However, it should be noted that acromegaly, which was reported to be the most commonly encountered symptom of plurihormonal adenoma, 2 , 3 was present in only around half of our patients. For patients with hyperprolactinaemia, the findings in our study concurred with those of previous reports that some were due to prolactin secretion of the adenoma, while some were related to stalk section effect rather than adenoma producing prolactin 9 …”

“…Most of the reports related to this group of tumours were: (i) studies of cases based on presenting symptoms, e.g. acromegaly; 6–9 (ii) studies of adenomas with immunohistochemical staining for a particular hormone in common, e.g. TSH; 10–12 or (iii) reports of distinct hormonal combinations in individual tumours 4 , 13–18 .…”

Expression of Adrenocorticotropic Hormone, Prolactin and Transcriptional Factors in Clinically Nonfunctioning Pituitary Adenoma

“…Generally, PRL levels are elevated in pituitary adenomas, mostly due to two possible mechanisms: 1) hypothalamic-pituitary disconnection, resulting in attenuation of PRL inhibitory factor, or 2) PRL-producing tumors [17,18]. Most PRL-producing tumors are diagnosed from very high PRL levels in blood.…”

Growth Hormone Suppression: Diagnosis of Growth Hormone Excess and Hyperprolactinemia

“…Immunohistochemical studies have shown that all tumors contain PRL-and GH-reactive cells [Furuhata et al, 1993]. Hyperprolactinemia may derive from a pituitary tumor which contains bipotential cells secreting GH and PRL or from two distinct adenomas producing various hormones.…”