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: "Rathke Cleft Cyst"
+docid: "8f1561f7-92a7-485c-a0ae-2e2d5c8c1628"
+breadcrumbs:
+  - "Brain"
+  - "Diagnosis"
+  - "Anatomy-Based Diagnoses"
+  - "Sella and Pituitary"
+  - "Congenital"
+  - "Rathke Cleft Cyst"
+---
+# KEY FACTS
+
+- ## Terminology
+  
+  
+    - Nonneoplastic cyst arising from remnants of embryonic Rathke cleft
+    - Benign, sellar region endodermal cyst lined by ciliated, mucus-producing epithelium
+- ## Imaging
+  
+  
+    - Nonenhancing, noncalcified, intrasellar &/or suprasellar cyst with intracystic nodule
+          - Completely intrasellar (40%), suprasellar extension (60%)
+          - Density/signal intensity varies with cyst content (serous vs. mucoid)
+    - Most symptomatic RCCs: 5-15 mm in diameter
+    - Occasionally RCCs can become very large
+    - Claw sign = enhancing rim of compressed pituitary surrounding nonenhancing cyst
+    - No internal enhancement
+- ## Top Differential Diagnoses
+  
+  
+    - Craniopharyngioma
+    - Cystic pituitary adenoma
+    - Arachnoid cyst
+    - Other nonneoplastic cyst (pars intermedia, colloid cyst)
+- ## Clinical Issues
+  
+  
+    - Most are asymptomatic, found incidentally at imaging or autopsy
+    - Common presenting features when symptomatic: Headache, pituitary dysfunction, visual changes
+    - Rare but important: Apoplexy, cavernous sinus syndrome
+          - Can be indistinguishable from pituitary apoplexy
+    - Conservative management if asymptomatic
+          - Have been reported to resolve without therapy
+    - Surgical aspiration, partial excision, or resection if symptomatic
+          - Recurrence rates in up to 18% of patients
+
+# TERMINOLOGY
+
+- ## Abbreviations
+  
+  
+    - Rathke cleft cyst (RCC)
+- ## Definitions
+  
+  
+    - Nonneoplastic cyst arising from remnants of embryonic Rathke cleft
+    - Benign, sellar region endodermal cyst lined by ciliated, mucus-producing epithelium
+
+# IMAGING
+
+- ## General Features
+  
+  
+    - ### Best diagnostic clue
+      
+      
+          - Nonenhancing, noncalcified, intrasellar &/or suprasellar cyst with intracystic nodule
+          - Uncommon but pathognomonic = posterior ledge sign
+                  - Upward extension through diaphragma sellae
+                  - Ledge of tissue overlies posterior lobe
+    - ### Location
+      
+      
+          - Completely intrasellar (40%), suprasellar extension (60%)
+          - Most Rathke cleft cysts are limited to sella
+                  - Between anterior, intermediate lobes
+          - Symptomatic Rathke clef cysts involve suprasellar location
+    - ### Size
+      
+      
+          - Most symptomatic Rathke cleft cysts 5-15 mm in diameter
+          - Occasionally become very large
+                  - May cause expansile, intrasellar/suprasellar mass
+                  - Rare: Erosion of skull base
+          - Size usually constant, does not enlarge
+                  - Transient decrease reported in response to glucocorticoids
+    - ### Morphology
+      
+      
+          - Well defined, round/ovoid
+- ## CT Findings
+  
+  
+    - ### NECT
+      
+      
+          - Well-delineated, round/lobulated, intra-/suprasellar mass
+                  - Hypodense (75%), mixed iso-/hypodense (20%)
+                  - Hyperdense (5-10%)
+                  - Ca⁺⁺ (10-15%), curvilinear, in cyst wall
+          - Rare: May cause sphenoid sinusitis
+    - ### CECT
+      
+      
+          - Does not enhance
+          - Occasionally see claw sign with normal pituitary gland surrounding cyst
+- ## MR Findings
+  
+  
+    - ### T1WI
+      
+      
+          - Varies with cyst content (serous vs. mucoid)
+                  - Hyperintense (50%), hypointense (50%)
+                  - Hyperintense, intracystic nodule (75%)
+                  - Mixed (5-10%), may have fluid-fluid level
+    - ### T2WI
+      
+      
+          - Varies with cyst content
+                  - Hyperintense (70%), iso-/hypointense (30%)
+                  - Hypointense, intracystic nodule (75%)
+    - ### FLAIR
+      
+      
+          - Hyperintense
+    - ### T2* GRE
+      
+      
+          - Rarely see susceptibility artifact
+    - ### T1WI C+
+      
+      
+          - No internal enhancement
+                  - Claw sign = enhancing rim of compressed pituitary surrounding nonenhancing cyst
+                  - Small, nonenhancing, intracystic nodule (75%)
+                  - If enhancing nodule present, likely craniopharyngioma
+- ## Imaging Recommendations
+  
+  
+    - ### Best imaging tool
+      
+      
+          - MR
+    - ### Protocol advice
+      
+      
+          - Thin-section, high-resolution imaging of sellar region
+          - Sagittal, coronal precontrast T1/T2 MR
+          - "Dynamic" coronal T1 C+ MR through sella
+          - Sagittal, coronal thin-section T1 C+ MR
+
+# DIFFERENTIAL DIAGNOSIS
+
+- [Craniopharyngioma](/document/craniopharyngioma/00e66680-6731-4287-b5a1-3f0b3f09053b)
+    - Histologic continuum between Rathke cleft cyst, craniopharyngioma
+    - Floccular Ca⁺⁺ common in craniopharyngioma, rare in Rathke cleft cyst
+    - Noncalcified RCC can be indistinguishable from craniopharyngioma on imaging
+    - Rim or nodular enhancement (90%)
+    - Cytokeratin profile helps distinguish from Rathke cleft cyst
+          - RCCs express cytokeratins 8, 20
+- [Cystic Pituitary Adenoma](/document/pituitary-microadenoma/283f3068-d369-4f79-bf01-0f2b82c6e49b)
+    - Ca⁺⁺ rare
+    - Signal intensity often heterogeneous
+    - Rim or rim with nodular enhancement common
+- [Arachnoid Cyst](/document/arachnoid-cyst/d25aaeb3-5b3c-4483-99dc-2757468eedb9)
+    - Follows CSF signal intensity
+    - Does not occur within pituitary gland
+    - No intracystic nodule
+- ## Other Nonneoplastic Cyst
+  
+  
+    - [Dermoid cyst](/document/dermoid-cyst/9b7aeb04-2cb3-405d-8c51-dd13297dd67c)
+          - May have short T1 signal related to fat or Ca⁺⁺
+          - Look for evidence of rupture
+    - [Epidermoid cyst](/document/epidermoid-cyst/704c5ddf-e1f7-4a5d-a1b8-5b0e603170d9)
+          - Mild irregular enhancement, Ca⁺⁺ (25%)
+          - DWI hyperintensity, FLAIR lack of suppression
+          - Otherwise follow CSF signal
+    - [Miscellaneous intrasellar cyst](/document/dermoid-cyst/9b7aeb04-2cb3-405d-8c51-dd13297dd67c)
+          - Pars intermedia, colloid cysts
+    - [Rare: Sellar/hypophyseal neurocysticercosis (NCC)](/document/neurocysticercosis/6a45835f-6d7c-443e-874a-f33131d3def1)
+          - May see racemose NCC in sellar/suprasellar region
+          - May rarely see scolex
+
+# PATHOLOGY
+
+- ## General Features
+  
+  
+    - ### Etiology
+      
+      
+          - One of spectrum of midline sellar/juxtasellar endodermal cysts
+          - Arises from embryonic remnants of fetal Rathke pouch
+                  - Rathke cleft normally regresses by 12th gestational week
+    - ### Genetics
+      
+      
+          - No known heritable conditions
+    - ### Associated abnormalities
+      
+      
+          - Sphenoid sinusitis (rare)
+          - Compression of optic chiasm, pituitary gland, hypothalamus
+                  - May cause hyperintensity on T2WI/FLAIR along optic chiasm, tracts
+          - Embryology
+                  - Persistence of Rathke pouch
+                  - Stomodeum (primitive oral cavity) invaginates
+                  - Extends dorsally, forms craniopharyngeal duct
+                  - Meets infundibulum (outgrowth of 3rd ventricle) by 11th fetal week, gives rise to hypophysis
+                  - Anterior wall of pouch forms anterior lobe, pars tuberalis
+                  - Posterior wall forms pars intermedia
+                  - Lumen forms narrow cleft (Rathke cleft) that normally regresses by 12th week of gestation
+                  - Persistence, expansion gives rise to RCC
+- ## Gross Pathologic & Surgical Features
+  
+  
+    - Smoothly lobulated, well-delineated, intrasellar/suprasellar cystic mass
+          - Content varies from clear CSF-like fluid to thick mucoid material
+- ## Microscopic Features
+  
+  
+    - Wall = single layer of ciliated cuboidal/columnar epithelium ± goblet cells
+          - Changes of mixed acute, chronic inflammation may be present
+    - May see squamous metaplasia (associated with increased rates of recurrent cysts)
+    - Variable cyst content
+          - Clear or serous
+          - ± hemorrhage, hemosiderin
+          - Amorphous, inspissated, eosinophilic, mucicarmine (+) colloid ± cholesterol clefts
+          - Firm, waxy, yellow, inspissated material
+          - Rare: Hemorrhage (cyst apoplexy)
+    - Immunohistochemical stains positive for cytokeratin
+          - Express cytokeratins 8, 20
+
+# CLINICAL ISSUES
+
+- ## Presentation
+  
+  
+    - ### Most common signs/symptoms
+      
+      
+          - Most are asymptomatic, found incidentally at imaging or autopsy
+                  - Found in up to ~ 20% of autopsy cases
+          - Symptomatic Rathke cleft cyst
+                  - Larger lesions, typically > 1 cm
+                  - Pituitary dysfunction (70%)
+                            - Amenorrhea/galactorrhea, diabetes insipidus, panhypopituitarism, hyperprolactinemia
+                  - Visual disturbances (45-55%)
+                  - Headache (50%)
+          - Other signs/symptoms
+                  - Head pain, visual disturbance
+                  - Hypopituitarism
+                  - Central diabetes insipidus
+          - Rare but important: Apoplexy, cavernous sinus syndrome
+                  - Cyst apoplexy
+                            - Can occur ± intracystic hemorrhage
+                            - Can be indistinguishable from pituitary apoplexy
+                  - Cavernous sinus syndrome
+                            - Caused by lateral extension of Rathke cleft cyst into cavernous sinus
+    - ### Clinical profile
+      
+      
+          - Asymptomatic most commonly
+- ## Demographics
+  
+  
+    - ### Age
+      
+      
+          - Mean: 45 years
+    - ### Sex
+      
+      
+          - Slight female predominance
+    - ### Epidemiology
+      
+      
+          - Common, intrasellar/suprasellar, nonneoplastic cyst
+          - Usually incidental, found in up to 20% of all autopsies
+- ## Natural History & Prognosis
+  
+  
+    - Most are stable, do not change in size/signal intensity
+    - Some cysts may shrink/disappear spontaneously
+    - Iso-/hyperintense cysts on T1 MR more often cause symptoms
+    - Rathke cleft cysts do not undergo neoplastic degeneration
+    - Some authors propose continuum from RCC to craniopharyngioma
+- ## Treatment
+  
+  
+    - Conservative if asymptomatic
+    - Surgical aspiration/partial excision/resection if symptomatic
+          - Persistent/recurrent cyst formation occurs in ~ 15-18% of patients
+          - May occur many years after surgery
+
+# DIAGNOSTIC CHECKLIST
+
+- ## Consider
+  
+  
+    - Obtaining endocrine profile
+- ## Image Interpretation Pearls
+  
+  
+    - Look for hypointense, intracystic nodule on T2 MR
+
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