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.

docs_md/articles/craniopharyngioma_00e66680-6731-4287-b5a1-3f0b3f09053b.md

@@ -0,0 +1,321 @@
+---
+title: "Craniopharyngioma"
+docid: "00e66680-6731-4287-b5a1-3f0b3f09053b"
+breadcrumbs:
+  - "Brain"
+  - "Diagnosis"
+  - "Anatomy-Based Diagnoses"
+  - "Sella and Pituitary"
+  - "Neoplasms"
+  - "Craniopharyngioma"
+---
+# KEY FACTS
+
+- ## Terminology
+  
+  
+    - Benign, partially cystic sellar region tumor derived from remnants of craniopharyngeal duct/Rathke pouch epithelium
+    - 2 types
+          - Adamantinomatous (cystic mass in childhood)
+          - Papillary (solid mass in older adults)
+- ## Imaging
+  
+  
+    - General features
+          - Multilobulated, often large (> 5 cm)
+          - Occasionally giant, multicompartmental
+    - CT: Cystic (90%), Ca⁺⁺ (90%), enhancing (90%)
+    - MR: Signal varies with cyst contents
+          - Cysts variably hyperintense on T1WI and T2WI
+          - Solid portions enhance heterogeneously; cyst walls enhance strongly
+          - Cyst contents show broad lipid peak (0.9-1.5 ppm) on MR spectroscopy
+- ## Pathology
+  
+  
+    - Most common pediatric intracranial tumor of nonglial origin
+    - WHO grade 1
+- ## Clinical Issues
+  
+  
+    - Bimodal age distribution
+          - Peak 5-15 years; adults 45-60 years (commonly papillary)
+    - Pediatric patient with morning headache, visual defect, short stature
+          - Endocrine disturbances include growth hormone (GH) deficiency, luteinizing hormone (LH)/follicle-stimulating hormone (FSH) deficiency
+          - Others = hypothyroidism > adrenal failure > diabetes insipidus
+    - Surgical resection is primary therapy
+    - Surgery, radiation therapy, or cyst aspiration for recurrent tumors
+
+# TERMINOLOGY
+
+- ## Abbreviations
+  
+  
+    - Craniopharyngioma (CP)
+- ## Synonyms
+  
+  
+    - Craniopharyngeal duct tumor, Rathke pouch tumor, adamantinoma
+- ## Definitions
+  
+  
+    - Benign, partially cystic sellar region tumor derived from Rathke pouch epithelium
+          - 2 histologies: Adamantinomatous and papillary
+
+# IMAGING
+
+- ## General Features
+  
+  
+    - ### Best diagnostic clue
+      
+      
+          - CT: Partially Ca⁺⁺ mixed solid/cystic suprasellar mass in child
+          - MR: Complex signal intensity suprasellar mass
+    - ### Location
+      
+      
+          - Surgical division of CPs into 3 groups
+                  - Sellar
+                  - Prechiasmatic
+                  - Retrochiasmatic
+          - Imaging locations of CPs (adamantinomatous type)
+                  - Suprasellar (75%)
+                  - Suprasellar + intrasellar component (21%)
+                  - Entirely intrasellar (4%)
+                  - Often extends into multiple cranial fossae: Anterior (30%), middle (23%), posterior, &/or retroclival (20%)
+          - Rare ectopic locations
+                  - Optic chiasm, 3rd ventricle
+                  - Other: Nasopharynx, paranasal sinuses, pineal gland, sphenoid (clivus), cerebellopontine angle
+    - ### Size
+      
+      
+          - Variable; often large at presentation (> 5 cm)
+                  - Occasionally giant, multicompartmental
+    - ### Morphology
+      
+      
+          - Multilobulated, multicystic
+- ## CT Findings
+  
+  
+    - ### NECT
+      
+      
+          - Adamantinomatous type (90% rule)
+                  - 90% mixed solid (isodense), cystic (hypodense)
+                  - 90% calcify
+                  - 90% enhance (solid = nodule; rim = capsule)
+          - Papillary type: Often solid, isodense, rarely calcifies
+- ## MR Findings
+  
+  
+    - ### T1WI
+      
+      
+          - Signal varies with cyst contents
+                  - Short T1 due to high protein content
+                  - Classic (adamantinomatous type)
+                            - Hyperintense cyst + heterogeneous nodule
+                  - Less common (papillary type)
+                            - Isointense solid component
+    - ### T2WI
+      
+      
+          - Cysts are variably hyperintense
+          - Solid component = heterogeneous (iso-/hyperintense, Ca⁺⁺ portions hypointense)
+          - Hyperintense signal in brain parenchyma adjacent to tumor may indicate
+                  - Gliosis, tumor invasion, irritation from leaking cyst fluid
+                  - Edema from compression of optic chiasm/tracts
+                  - Hypointense T2* = Ca⁺⁺
+    - ### FLAIR
+      
+      
+          - Cyst contents typically hyperintense
+    - ### DWI
+      
+      
+          - Variable depending upon character of cyst fluid
+    - ### T1WI C+
+      
+      
+          - Solid portions enhance heterogeneously; cyst walls enhance strongly
+    - ### MRA
+      
+      
+          - Vascular displacement &/or encasement
+    - ### MRS
+      
+      
+          - Cyst contents show broad lipid spectrum (0.9-1.5 ppm)
+- ## Imaging Recommendations
+  
+  
+    - ### Best imaging tool
+      
+      
+          - MR with thin sagittal, coronal sequences
+    - ### Protocol advice
+      
+      
+          - Pre-/postcontrast T1WI, T2, FLAIR, GRE, DWI, MRS
+
+# DIFFERENTIAL DIAGNOSIS
+
+- [Rathke Cleft Cyst](/document/rathke-cleft-cyst/8f1561f7-92a7-485c-a0ae-2e2d5c8c1628)
+    - Noncalcified, less heterogeneous
+    - Look for intracystic nodule on T2
+    - Does not enhance
+          - Claw sign (enhancing pituitary draped around cyst)
+    - Small Rathke cleft cyst (RCC) may be indistinguishable from rare intrasellar CP
+    - RCCs express CK8 and CK20 (CPs generally do not)
+- ## Suprasellar Arachnoid Cyst
+  
+  
+    - No Ca⁺⁺, enhancement
+- ## Hypothalamic/Chiasmatic Astrocytoma
+  
+  
+    - Solid or with small cystic/necrotic components
+    - Ca⁺⁺ is rare; robust enhancement is common
+- ## Pituitary Adenoma
+  
+  
+    - Rare in prepubescent children
+    - Isointense with brain
+    - Enhances strongly
+    - Can mimic CP when cystic and hemorrhagic
+- ## Epidermoid/Dermoid Tumors
+  
+  
+    - Minimal or no enhancement
+- ## Thrombosed Aneurysm
+  
+  
+    - Contains blood products; use SWI
+    - Look for residual patent lumen, phase artifact
+- [Germinoma or Mixed Germ Cell Tumor With Cystic Component(s)](/document/germinoma/078b68a2-67de-457e-818a-63655cec95aa)
+    - Cerebrospinal fluid spread is common, Ca⁺⁺ is rare
+
+# PATHOLOGY
+
+- ## General Features
+  
+  
+    - ### Etiology
+      
+      
+          - 2 proposed theories
+                  - CPs arise from remnants of craniopharyngeal duct and Rathke pouch epithelium
+                  - CPs arise from squamous epithelial cells in pars tuberalis of adenohypophysis
+    - ### Genetics
+      
+      
+          - No known genetic susceptibility (rare reports of siblings, parent-child)
+          - Small subset of CPs are monoclonal tumors that arise from oncogenes at specific loci
+          - Adamantinomatous: *CTNNB1* mutations and aberrant nuclear expression of β-catenin in up to 95% of cases
+          - Papillary:*BRAF* V600E mutations in 81-95% of cases
+- ## Staging, Grading, & Classification
+  
+  
+    - WHO grade 1
+    - MIB-1 labeling index > 7% predicts recurrence
+- ## Gross Pathologic & Surgical Features
+  
+  
+    - Solid tumor with variable cysts
+    - Adamantinomatous cysts often contain thick "crankcase oil" fluid
+    - Epithelial fronds penetrate adjacent hypothalamus/chiasm
+- ## Microscopic Features
+  
+  
+    - Adamantinomatous (mostly pediatric)
+          - Multistratified squamous epithelium with nuclear palisading
+          - Nodules of "wet" keratin
+          - Dystrophic Ca⁺⁺
+    - Papillary (mostly adults)
+          - Sheets of squamous epithelium form pseudopapillae
+          - Villous fibrovascular stroma
+    - Malignant transformation, distant metastases rare
+          - May occur with varied histologies, resulting in poor prognosis
+
+# CLINICAL ISSUES
+
+- ## Presentation
+  
+  
+    - ### Most common signs/symptoms
+      
+      
+          - Symptoms vary with location, size of tumor, age of patient
+          - Visual disturbances (60-85%)
+                  - Bitemporal hemianopsia
+    - ### Other signs/symptoms
+      
+      
+          - Endocrine disturbances (52-87%)
+                  - Growth hormone (GH) deficiency (75%) > luteinizing hormone (LH)/follicle-stimulating hormone (FSH) deficiency > hypothyroidism > adrenal failure > diabetes insipidus
+                  - Headaches
+                  - Cognitive impairment (~ 50%)
+    - ### Clinical profile
+      
+      
+          - Pediatric patient with morning headache, visual defect, short stature
+- ## Demographics
+  
+  
+    - ### Age
+      
+      
+          - Bimodal distribution (peak 5-15 years, with smaller peak 45-60 years)
+                  - Papillary CP: 40-55 years
+    - ### Sex
+      
+      
+          - M = F
+    - ### Ethnicity
+      
+      
+          - More common in Japanese children
+    - ### Epidemiology
+      
+      
+          - Most common pediatric intracranial tumor of nonglial origin
+          - Comprise 1.2-4.6% of all intracranial tumors across all ages
+                  - 6-11% of all pediatric intracranial tumors
+                  - Incidence = 0.5-2.5 new cases per 1 million per year
+          - ~ 54% of all pediatric sellar/chiasmatic region tumors are CPs
+- ## Natural History & Prognosis
+  
+  
+    - Typically slow-growing benign neoplasm
+    - Prognosis based upon size, extent of tumor at presentation
+          - < 5 cm, recurrence rate: 20%
+          - > 5 cm, recurrence rate: 83%
+          - Overall 10-year survival: 64-96%
+- ## Treatment
+  
+  
+    - Methods of primary treatment
+          - Radical surgery = gross total resection
+                  - Complications = hypothalamic injury, endocrine symptoms, vasa vasorum injury, and pseudoaneurysm
+          - Surgery may occur via craniotomy, transnasal, transorbital, or endoscopic routes
+          - Less invasive surgery = subtotal resection + radiation therapy
+          - Biopsy, cyst drainage, and radiation therapy
+    - Treatment for residual or recurrent tumor
+          - Surgery, radiation therapy, or cyst aspiration
+          - Cyst instillation with intracavitary radioisotopes, bleomycin, or other sclerosing agents
+
+# DIAGNOSTIC CHECKLIST
+
+- ## Consider
+  
+  
+    - Preoperative ophthalmologic and endocrine evaluations
+- ## Image Interpretation Pearls
+  
+  
+    - Use NECT to detect Ca⁺⁺ if MR diagnosis is in question
+    - Adamantinomatous CP = 90% rule (90% cystic, calcified, enhancing)
+    - Papillary CP is typically solid and primarily adult neoplasm
+
+ c497473c-5835-4221-bfa1-0d2be04bee73