Files

T

Ross 9c86b32c3b .

2025-10-20 21:15:33 +01:00

41 KiB

Raw Blame History

title, docid, authors, breadcrumbs, category, cmeTopicId, documentVersionId, imageCount, lastUpdated, pageDescription, pageKeywords, pageTitle, enhancedTitle, type, references, breadcrumbs

title

docid

authors

breadcrumbs

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
- 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
- Ca⁺⁺ rare
- Signal intensity often heterogeneous
- Rim or rim with nodular enhancement common
Arachnoid Cyst
- Follows CSF signal intensity
- Does not occur within pituitary gland
- No intracystic nodule
Other Nonneoplastic Cyst
- Dermoid cyst - May have short T1 signal related to fat or Ca⁺⁺ - Look for evidence of rupture
- Epidermoid cyst - Mild irregular enhancement, Ca⁺⁺ (25%) - DWI hyperintensity, FLAIR lack of suppression - Otherwise follow CSF signal
- Miscellaneous intrasellar cyst - Pars intermedia, colloid cysts
- Rare: Sellar/hypophyseal neurocysticercosis (NCC) - 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

7627570e-5f61-4f2f-9e4d-fb044c354667

References

Selected References

Images

Selected Images

Coronal graphic shows a typical suprasellar Rathke cleft cyst interposed between the pituitary gland and the optic chiasm . The majority of Rathke cleft cysts are both sellar and suprasellar.

Coronal T1 MR in a 21-year-old woman with amenorrhea shows a hyperintense sellar and suprasellar mass . Rathke cleft cyst was found at resection. Mass effect from the lesion size caused symptoms in this case. Small Rathke cleft cysts are most commonly asymptomatic and may be managed conservatively.

Coronal T1 C+ MR in a 62-year-old woman with headaches shows a cystic suprasellar mass with mild peripheral enhancement, a claw sign related to compression of the adjacent normal pituitary gland by the Rathke cleft cyst. Note the lack of enhancement within the cyst.

Coronal T2 MR in the same patient shows a hyperintense cyst with a hypointense, intracystic nodule . An intracystic nodule may be seen in up to 75% of Rathke cleft cysts and is a helpful clue to the correct diagnosis.

Sagittal T1 MR in a patient with amenorrhea shows a hyperintense mass within the pituitary gland anterior to the normal hyperintense neurohypophysis . Imaging mimics a hemorrhagic pituitary microadenoma. Rathke cleft cyst was found at resection.

Coronal T1 C+ MR shows a sellar and suprasellar RCC with a claw sign of compressed pituitary gland surrounding the mass. Note the superior displacement of the optic chiasm draped over the mass in this patient with visual changes.

Sagittal NECT in a patient with a headache shows a hypodense, intrasellar mass with mild suprasellar extension , a typical CT appearance of Rathke cleft cyst. Note the lack of calcification, which helps distinguish RCC from craniopharyngiomas, which are typically calcified (90%).

Sagittal T1 C+ MR shows typical appearance of Rathke cleft cyst between normal adenohypophysis anteriorly and neurohypophysis posteriorly . Small lesions may be managed conservatively.

Sagittal T1 C+ MR shows a sellar and suprasellar Rathke cleft cyst with a classic claw sign of compressed pituitary gland surrounding the nonenhancing mass. Rathke cleft cyst was confirmed at surgery.

Coronal T2 MR in the same patient shows marked hypointensity within the cyst . Cyst contents may have variable signal. There is mild mass effect and superior displacement of the optic chiasm in this male patient who presented with visual changes.

Additional Images

Sagittal T1 MR shows a well-delineated, hyperintense, suprasellar mass that is clearly distinct from the pituitary gland. Rathke cleft cyst was documented at surgery.

Coronal T1 MR shows a classic Rathke cleft cyst that elevates and drapes the optic chiasm. The pituitary gland is normal.

Coronal T2 MR shows that most of the suprasellar mass is isointense with gray matter. Note the focal, hypointense nodule , virtually pathognomonic of a Rathke cleft cyst.

Coronal T1 C+ MR shows very large combined intra- and suprasellar cystic mass. Note the rim enhancement with a nonenhancing layer of debris within the cyst. Rathke cleft cyst was found at surgery.

Sagittal T1 C+ MR shows the 3rd ventricle is elevated and draped over the mass.

Sagittal T2 MR shows a well-delineated, extremely hypointense mass found incidentally in an asymptomatic patient. This was presumed to be a Rathke cleft cyst.

Coronal T2 MR in 2-year-old child shows a huge cyst with intra- and suprasellar components. A large Rathke cleft cyst was found at surgery.

Sagittal T1 MR in a patient with a headache but no neurologic symptoms shows a small, hypointense cyst that followed CSF on all sequences. It was an incidental finding and presumed to be a Rathke cleft cyst.

Sagittal T1 C+ FS MR shows a Rathke cleft cyst with claw sign of residual enhancing pituitary gland draped around the large, intra- and suprasellar cyst.

Axial NECT shows a hypodense, CSF-like intra- and suprasellar mass . Rathke cleft cyst was found at surgery.

Coronal T1 MR in an asymptomatic patient shows a small, suprasellar mass that is isointense with the brain clearly separate from the pituitary gland . The infundibular stalk is slightly deviated to the left. This was presumed to be a Rathke cleft cyst.

Coronal T2 MR in the same patient demonstrates that the cyst is primarily hypointense. Note the intracystic nodule . Rathke cleft cyst was found at surgery.

Coronal T1 MR in a 21-year-old woman, with sudden-onset headache and decreased T4, shows a hyperintense mass with even more hyperintense intracystic nodules . The preoperative diagnosis was pituitary apoplexy, and Rathke cleft cyst apoplexy was found at surgery.

Coronal T1 MR in a 48-year-old man with headache shows a hyperintense, sellar mass with normal surrounding pituitary tissue.

Coronal T2 MR in the same patient shows the mass is hypointense and enlarges the pituitary gland. There is no compression of the optic chiasm . No enhancement of the lesion was present on postcontrast imaging (not shown). Rathke cleft cyst was confirmed at resection.

Coronal NECT in a patient with a headache shows a hyperdense, intrasellar mass with minimal suprasellar extension . Rathke cleft cysts are most commonly hypodense on CT. Note the lack of calcification, which helps distinguish RCC from craniopharyngiomas, which are typically calcified (90%).

Axial gross pathology shows a mucinous-containing Rathke cleft cyst found incidentally at autopsy. (Courtesy E. Hedley-Whyte, MD.)

Coronal T1 C+ MR shows a sellar and suprasellar Rathke cleft cyst with a classic claw sign of compressed pituitary gland surrounding the nonenhancing mass. Note the superior displacement of the optic chiasm as it is draped over the mass .

41 KiB Raw Blame History

KEY FACTS

Terminology

Imaging

Top Differential Diagnoses

Clinical Issues

TERMINOLOGY

Abbreviations

Definitions

IMAGING

General Features

Best diagnostic clue

Location

Size

Morphology

CT Findings

NECT

CECT

MR Findings

T1WI

T2WI

FLAIR

T2* GRE

T1WI C+

Imaging Recommendations

Best imaging tool

Protocol advice

DIFFERENTIAL DIAGNOSIS

Other Nonneoplastic Cyst

PATHOLOGY

General Features

Etiology

Genetics

Associated abnormalities

Gross Pathologic & Surgical Features

Microscopic Features

CLINICAL ISSUES

Presentation

Most common signs/symptoms

Clinical profile

Demographics

Age

Sex

Epidemiology

Natural History & Prognosis

Treatment

DIAGNOSTIC CHECKLIST

Consider

Image Interpretation Pearls

References

Selected References

Images

Selected Images

Additional Images

41 KiB

Raw Blame History