# Lactotroph pituitary neuroendocrine tumour (prolactinoma)

Source: https://onco.cc/cancers/lactotroph-pitnet/  
OnCo record `lactotroph-pitnet` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A prolactinoma is a pituitary tumour of the cells that make prolactin, the milk hormone; it is the commonest hormone-producing pituitary tumour and causes missed periods, infertility, milk production or, in men, low testosterone. Almost uniquely among tumours it is treated first with a tablet, cabergoline, which shrinks it in most people; surgery is kept for those the drug fails.

## Summary

The 2022 WHO classification of endocrine tumours reclassifies pituitary adenomas as pituitary neuroendocrine tumours (PitNETs) and types them by transcription factor lineage, the lactotroph tumour belonging to the PIT1 lineage with sparsely or densely granulated subtypes, defined by prolactin and oestrogen receptor alpha expression (Asa 2022). The Pituitary Society's 2023 international consensus covers epidemiology, biochemical evaluation of hyperprolactinaemia, imaging, treatment with dopamine agonists including efficacy, adverse effects and withdrawal, indications for surgery and radiotherapy, and management in pregnancy, children, psychiatric illness, postmenopausal women, transgender people and kidney disease; it concludes that treatment resistance is rare but that new options and international registries are needed (Petersenn 2023).

How it differs from its parent: the parent page covers all pituitary tumours; the lactotroph tumour is the one treated medically first, the one whose macroadenomas in women and men respond to cabergoline with tumour shrinkage, and the one where surgery has become a first-line alternative for small well-defined tumours in some guidelines.

How common: the most prevalent functioning pituitary tumour (Petersenn 2023); no separate incidence figure in the sources read.

Treatment: cabergoline (or bromocriptine) as first-line therapy with attempted withdrawal after prolonged normalisation and tumour shrinkage; transsphenoidal surgery for intolerance, resistance, cystic tumours or patient preference; radiotherapy and temozolomide for the rare aggressive or giant prolactinoma, as on the parent page (Petersenn 2023).

## Fields

- Kind: Cancer
- Last checked: 2026-09-24
- Also known as: Prolactinoma; Lactotroph tumour; Lactotroph tumour (prolactinoma); Prolactin-secreting pituitary adenoma; Lactotroph adenoma
- Tags: subtype-page; wave4; rare
- Group: endocrine
- Burden: The most prevalent functioning pituitary tumour (Pituitary Society consensus 2023); the parent page gives the pituitary tumour figures, and GLOBOCAN does not count pituitary tumours.
- Subtypes: Sparsely granulated lactotroph pituitary tumour (the common prolactinoma); Densely granulated lactotroph pituitary tumour; Giant or aggressive prolactinoma (dopamine agonist-resistant); Mixed somatotroph-lactotroph or mammosomatotroph tumour (PIT1 lineage)
- Biomarkers: Serum prolactin (with macroprolactin and hook-effect checks); PIT1 and oestrogen receptor alpha lineage markers; prolactin immunostaining; Pituitary MRI (micro- versus macroadenoma; cavernous sinus invasion); Ki-67 and mitoses (aggressiveness)

## Sections of this record

The page is a hub with ten sections in reading order; large sections have their own page. The same plan as JSON: https://onco.cc/api/v1/cancers/lactotroph-pitnet/sections.json

- Overview (on the hub): The TL;DR, the family this cancer belongs to, the organ, who gets it and what the state of the art is. https://onco.cc/cancers/lactotroph-pitnet/#overview
- What it is (on the hub): Anatomy, the subtypes and how they differ, how it is staged, and where advanced disease spreads. https://onco.cc/cancers/lactotroph-pitnet/#what-it-is [4 subtypes]
- Finding it (on the hub): How it shows itself, how it is confirmed, what screening exists, and the biomarkers clinicians test for. https://onco.cc/cancers/lactotroph-pitnet/#finding-it [4 biomarkers]
- Treating it (on the hub): The standard of care by setting, the medicines, surgery and radiotherapy named in it, and the regimens behind them. https://onco.cc/cancers/lactotroph-pitnet/#treating-it [2 settings, 2 decisions with options]
- Evidence (on the hub): Trials recruiting now, the landmark trials, the key papers and what they mean, the latest literature, and the milestones year by year. https://onco.cc/cancers/lactotroph-pitnet/#evidence
- The science (on the hub): The molecular landscape: the targets and how often each appears, the pathways, the mechanics stages and the preclinical models. https://onco.cc/cancers/lactotroph-pitnet/#science [1 target]
- Where you are (own page): Cases by country, the UK and NHS pathway and other country lenses, and the expert centres with trials on record. https://onco.cc/cancers/lactotroph-pitnet/where-you-are/
- Living with it (on the hub): The decisions you may face, the aids that walk through them, the warnings on record, the first sixty days and the questions to ask. https://onco.cc/cancers/lactotroph-pitnet/#living-with-it [10 questions, 2 red cards]
- What is coming (own page): Everything in development, the open problems and what is being done about them, the roadmaps, and what changed on this record. https://onco.cc/cancers/lactotroph-pitnet/coming/ [3 medicines]
- Data (own page): Every connected record, the notes, the JSON, Markdown and RDF twins, and where the record came from and when it was checked. https://onco.cc/cancers/lactotroph-pitnet/data/ [10 connected records]

## Standard of care

- First line: Cabergoline (or bromocriptine), with attempted withdrawal after prolonged normalisation and shrinkage. ([Cabergoline](https://onco.cc/drugs/cabergoline/), [Bromocriptine](https://onco.cc/drugs/bromocriptine/), [Pituitary tumours (pituitary neuroendocrine tumours) and pituitary carcinoma](https://onco.cc/cancers/pituitary-tumours/))
- Resistant, intolerant or aggressive: Transsphenoidal surgery; radiotherapy and temozolomide for aggressive or giant tumours as on the parent page. ([Stereotactic radiosurgery (Gamma Knife, CyberKnife, linac SRS)](https://onco.cc/technologies/radiosurgery-srs/), [Temozolomide](https://onco.cc/drugs/temozolomide/), [Pituitary tumours (pituitary neuroendocrine tumours) and pituitary carcinoma](https://onco.cc/cancers/pituitary-tumours/))

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Prolactinoma
- NCI PDQ: pituitary tumours treatment: https://www.cancer.gov/types/pituitary/treatment
- Asa 2022, Endocrine Pathology: overview of the 2022 WHO classification of pituitary tumours: https://doi.org/10.1007/s12022-022-09703-7
- Petersenn 2023, Nature Reviews Endocrinology: Pituitary Society international consensus on prolactin-secreting pituitary adenomas: https://doi.org/10.1038/s41574-023-00886-5

## Connected records

- cancers: [Corticotroph pituitary neuroendocrine tumour (Cushing disease and silent corticotroph tumour)](https://onco.cc/cancers/corticotroph-pitnet/), [Gonadotroph pituitary neuroendocrine tumour (non-functioning adenoma)](https://onco.cc/cancers/gonadotroph-pitnet/), [Multiple endocrine neoplasia type 1 (MEN1)](https://onco.cc/cancers/men1-syndrome/), [Pituitary tumours (pituitary neuroendocrine tumours) and pituitary carcinoma](https://onco.cc/cancers/pituitary-tumours/), [Somatotroph pituitary neuroendocrine tumour (acromegaly)](https://onco.cc/cancers/somatotroph-pitnet/), [Thyrotroph pituitary neuroendocrine tumour (TSH-secreting)](https://onco.cc/cancers/thyrotroph-pitnet/)
- technologies: [Stereotactic radiosurgery (Gamma Knife, CyberKnife, linac SRS)](https://onco.cc/technologies/radiosurgery-srs/)
- drugs: [Bromocriptine](https://onco.cc/drugs/bromocriptine/), [Cabergoline](https://onco.cc/drugs/cabergoline/), [Temozolomide](https://onco.cc/drugs/temozolomide/)

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JSON: https://onco.cc/api/v1/entities/lactotroph-pitnet.json