Table 1.
Classification of Pituitary Adenomas
| Size | Function | Hormone | Pathology (WHO)a | Morphofunctional subclassificationa |
|---|---|---|---|---|
| Microadenoma Macroadenoma Giant adenoma |
Functioning Non-functioning |
Prolactin | Lactotroph adenoma (LA) | Sparsely granulated LA Densely granulated LA Acidophilic stem cell adenoma |
| Growth hormone | Somatotroph adenoma (SA) | Densely granulated SA Sparsely granulated SA Mammosomatotroph adenoma Mixed somatotroph and lactotroph adenoma |
||
| Adrenocorticotropic hormone | Corticotroph adenoma (CA) | Sparsely granulated CA Densely granulated CA Acidophilic stem cell adenoma |
||
| Thyroid-stimulating hormone | Thyrotroph adenoma | |||
| Luteinizing hormone/follicular-stimulating hormone | Gonadotroph adenoma (GA) null cell adenoma | Sparsely granulated GA | ||
| Plurihormonal | Plurihormonal adenoma | Plurihormonal PIT1-positive adenoma Adenomas with unusual IHC combinations |
||
| Double adenoma | Distinct adenomas |
WHO, World Health Organization; PIT1, pituitary-specific positive transcription factor 1; IHC, immunohistochemical.
a
Adapted from Laws et al. [10], with permission from Springer Nature.