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---
-title: "Pituitary Hyperplasia"
-docid: "9696bc9e-f00b-4fa7-aa67-f039efd8fbed"
-breadcrumbs:
-  - "Brain"
-  - "Diagnosis"
-  - "Anatomy-Based Diagnoses"
-  - "Sella and Pituitary"
-  - "Miscellaneous"
-  - "Pituitary Hyperplasia"
---
-# KEY FACTS
-
- ## Terminology
-  
-  
-    - Normal maximal pituitary height varies with age, sex
-          - Pregnant/lactating females: 12 mm
-          - Young menstruating females: 10 mm
-          - Males, postmenopausal females: 8 mm
-          - Infants, children: 6 mm
-    - Nonphysiologic hyperplasia seen with
-          - Hypothyroidism, Addison disease, or other end-organ failure
-          - Some neuroendocrine neoplasms
- ## Imaging
-  
-  
-    - Enlarged homogeneously enhancing pituitary gland with convex superior margin
-    - Best technique: High-resolution MR
-          - Sagittal/coronal T1; coronal T2
-          - Dynamic coronal T1WI
-          - Postcontrast T1 FS sagittal/coronal T1
-          - 3- to 4-mm slice thickness
- ## Top Differential Diagnoses
-  
-  
-    - Pituitary macroadenoma
-    - Pituitary microadenoma
-    - Lymphocytic hypophysitis
-    - Venous congestion (intracranial hypotension, dural arteriovenous fistula)
- ## Pathology
-  
-  
-    - Normal: Physiologic hyperplasia in pregnancy, lactation
-    - Abnormal: Longstanding untreated primary hypothyroidism
-          - Loss of thyroxine feedback inhibition, overproduction of thyrotropin-releasing hormone
-          - Secondary pituitary hyperplasia
-                  - Orthotopic or ectopic production of hypothalamic-releasing hormones
-                  - Orthotopic: Response to end-organ failure
-                  - Ectopic: Related to neuroendocrine tumors
-
-# TERMINOLOGY
-
- ## Definitions
-  
-  
-    - Upper limit of normal pituitary height varies with age, sex
-          - Pregnant/lactating females: 12 mm
-          - Young menstruating females: 10 mm
-          - Males, postmenopausal females: 8 mm
-          - Infants, children: 6 mm
-    - Nonphysiologic pituitary hyperplasia seen with
-          - Longstanding untreated primary hypothyroidism
-          - Addison disease, end-organ failure, some neuroendocrine neoplasms
-
-# IMAGING
-
- ## General Features
-  
-  
-    - ### Best diagnostic clue
-      
-      
-          - Enlarged homogeneously enhancing pituitary gland with convex superior margin
-                  - > 10 mm up to 15 mm
-          - May be nodular, mimic pituitary adenoma
-    - ### Location
-      
-      
-          - Sella; may extend into suprasellar region, compress adjacent structures
- ## CT Findings
-  
-  
-    - ### NECT
-      
-      
-          - Noncalcified pituitary gland enlargement
-    - ### CECT
-      
-      
-          - Homogeneous enhancement
- ## MR Findings
-  
-  
-    - ### T1WI
-      
-      
-          - Isointense with remainder of pituitary gland
-    - ### T2WI
-      
-      
-          - Isointense with remainder of pituitary gland
-    - ### T1WI C+
-      
-      
-          - Diffusely enhancing gland is typical
-                  - Rare = may cause focal nodular enlargement
-          - Dynamic MR: Enhances similar to remainder of gland
- ## Imaging Recommendations
-  
-  
-    - ### Best imaging tool
-      
-      
-          - MR with 3- to 4-mm slices, small FOV
-    - ### Protocol advice
-      
-      
-          - Sagittal/coronal T1; coronal T2
-          - Dynamic enhanced coronal T1WI
-          - Postcontrast T1 FS sagittal/coronal
-
-# DIFFERENTIAL DIAGNOSIS
-
- [Pituitary Macroadenoma](/document/pituitary-microadenoma/283f3068-d369-4f79-bf01-0f2b82c6e49b)
-    - May be indistinguishable
-    - Rare: May occur secondary to primary hypothyroidism
- [Pituitary Microadenoma](/document/pituitary-microadenoma/283f3068-d369-4f79-bf01-0f2b82c6e49b)
-    - May be indistinguishable
-    - Enhances slower than normal gland on dynamic study
- [Lymphocytic Hypophysitis](/document/lymphocytic-hypophysitis/f30774c3-cbd0-4ab3-b3d1-e0574106db1f)
-    - Enlarged gland &/or stalk
-    - Pregnant or postpartum females
- ## Venous Congestion
-  
-  
-    - [Can occur with intracranial hypotension](/document/intracranial-hypotension/818a7972-1032-4d3e-a65a-97c494334aac)
-    - [Dural arteriovenous fistulas](/document/dural-av-fistula/628fd160-1e22-4b55-83f9-c25464d05bd6)
-
-# PATHOLOGY
-
- ## General Features
-  
-  
-    - ### Etiology
-      
-      
-          - Normal: Physiologic hyperplasia in pregnancy, lactation
-          - Longstanding untreated primary hypothyroidism
-                  - Loss of thyroxine feedback inhibition, overproduction of thyrotropin-releasing hormone
-                  - Secondary pituitary hyperplasia
-                            - Orthotopic or ectopic production of hypothalamic-releasing hormones
-                            - Orthotopic: Response to end-organ failure
-                            - Ectopic: Related to neuroendocrine tumors
- ## Microscopic Features
-  
-  
-    - Nodular hyperplasia characterized by marked expansion of acini, architectural distortion
-    - Diffuse hyperplasia requires formal cell count
-    - Growth hormone cell hyperplasia usually diffuse, occurs with neuroendocrine tumors
-          - Pancreatic islet cell tumor, pheochromocytoma, and bronchial and thyroid carcinoid tumors
-          - Associated with McCune-Albright syndrome, multiple endocrine neoplasia syndrome, and Carney complex
-    - Prolactin cell hyperplasia: Diffuse > nodular
-          - May be seen with pregnancy and lactation, estrogen treatment, primary hypothyroidism, Cushing disease
-    - Corticotroph hyperplasia: Nodular or diffuse
-          - Associated with Cushing disease, neuroendocrine tumors, untreated Addison disease
-    - Thyrotroph hyperplasia
-          - Longstanding primary hypothyroidism, may have associated prolactin hyperplasia
-    - Gonadotroph hyperplasia (e.g., Turner, Klinefelter syndromes)
-
-# CLINICAL ISSUES
-
- ## Presentation
-  
-  
-    - ### Most common signs/symptoms
-      
-      
-          - Varies with cell type of hyperplasia
- ## Demographics
-  
-  
-    - ### Age
-      
-      
-          - Typically adults (rare in children)
-    - ### Sex
-      
-      
-          - No predilection
- ## Treatment
-  
-  
-    - If related to hypothyroidism, regression after thyroid hormone therapy common
-    - Treat end-organ failure or neuroendocrine tumor
-
-# DIAGNOSTIC CHECKLIST
-
- ## Consider
-  
-  
-    - Hyperplasia may mimic adenoma
-          - Clinical information can help differentiate
-    - If imaging looks like adenoma in prepubescent male, consider end-organ failure
-
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