Health Dictionary
Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.
Growth hormone secreting pituitary adenoma
Introduction
Overview
Overview
Pituitary adenoma may be classified according to the size of the adenoma and type of hormone secretion, subtypes include corticotrophic, somatotrophic, thyrotrophic, gonadotrophic, and lactrotrophic adenomas.
Classification
Classification
- Historically, pituitary tumors were classified as basophilic, acidophilic, or chromophobic based on the positivity of hematoxylin and eosin stain.
- Newer classification is based on either the size or the functional status of the adenoma (secretory vs. non-secretory).
Classification based on hormone secretion and immunohistochemical staining
| Type of adenoma | Secretion | Staining | Pathology |
| Corticotrophic adenomas | Adrenocorticotropic hormone (ACTH) and pro-opiomelanocortin (POMC) | Basophilic | Cushing’s disease |
| Somatotrophic adenomas | Growth hormone (GH) | Acidophilic | Acromegaly (gigantism) |
| Thyrotrophic adenomas (rare) | Thyroid-stimulating hormone (TSH) | Basophilic | Occasionally hyperthyroidism/Asymptomatic |
| Gonadotrophic adenomas | Luteinizing hormone (LH), follicle-stimulating hormone (FSH) and their subunits | Basophilic | Asymptomatic |
| Lactrotrophic adenomas or prolactinomas (most common) | Prolactin | Acidophilic | Galactorrhea, hypogonadism, amenorrhea, infertility, and impotence |
| Null cell adenomas | Do not secrete hormones | May stain positive for synaptophysin |
Classification based on the size of the adenoma
Pituitary adenoma may be classified into 4 grades based on radioanatomical:[1]
- Stage I involves microadenomas (<1 cm) without sella expansion
- Stage II involves macroadenomas (≥1 cm) and may extend above the sella
- Stage III involves macroadenomas with enlargement and invasion of the floor or suprasellar extension
- Stage IV involves macroadenomas that cause destruction of the sella
References
References
- ↑ Pituitary adenoma (2015). http://www.cancer.gov/types/pituitary/hp/pituitary-treatment-pdq#section/_96. Accessed on 9/28/2015. Invalid parameter “cancer” in
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Ahmad Al Maradni, M.D. [2]