| Incidental prolactinoma |
| Found while investigating an unrelated finding, without signs or symptoms attributed to prolactinoma, with normal endocrine function AND diameter < 10 mm AND pretreatment prolactin < 200 |
| Microprolactinoma |
| Diameter < 10 mm AND pretreatment prolactin < 200 |
| Macroprolactinoma |
| Diameter 10 mm or greater OR pretreatment prolactin 200 - 500 |
| Giant, extrasellar, suprasellar or infrasellar prolactinoma |
| Extends outside the pituitary OR pretreatment prolactin > 500 |
