Macroadenoma

MICROADENOMA.:Few words which I like to convey-little discussed by us:-Of all pit adenomas 30-40% if al Pit adenomas, & 10% of all intracranial neoplasms. There is one syndrome called Type 1 Syndrome where genetic change is that there are multiple endocrine tumours in the same person. Most Lactotrophs tumours are benign. If adenoma size is < 1 cm the n usual serum level is 200 ng/ml. but if size is 1 cm to 2 cm in diameter than PRL vale may exceed 1000 ng/ml/Above such dia the level can be higher still.

Pitfalls in the assay report:-If cystic adenoma-then serum level may not correlate with the size of tumour.Artifact in the immunoradiometric assay.-if too low in a case of tumour then dilutes the sera- will yield appropriate result. (Hook effect).Any disease or tumour near Hypothalamus can impede secretion of PIFà rise of PRL. Head trauma, Craniopharyngioma, infiltrative diseases if brain, Kochs, malig deposits.

Hypothyroidism- Hypothyroidism per see usually do not cause rise of basal PRL. What happens is that in cases of hypothyroidism if TRH is administered as a challenge dose then PRL will rise. due to the effect of raised TRH. MRI of Pit may be solo enlargement of thyrotrophic adenoma and not Lactotrophs adenoma