Add comprehensive articles on Vascular Dementia and Wallerian Degeneration

- Created a detailed article for Vascular Dementia covering key facts, terminology, imaging findings, differential diagnoses, pathology, clinical issues, and diagnostic checklist. - Developed an extensive article on Wallerian Degeneration including key facts, terminology, imaging features, differential diagnoses, pathology, clinical issues, and diagnostic checklist.
2025-10-17 22:11:27 +01:00
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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
+
+ f1e3a750-ebdd-439c-8134-0efe1099c891