CNS tumor
Sellar region tumors

Topic Completed: 1 March 2017

Minor changes: 29 September 2020

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PubMed Search: Adamantinomatous craniopharyngioma

Related topics: Papillary craniopharyngioma

Nelli S. Lakis M.D., M.Sc.
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Cite this page: Lakis NS. Craniopharyngioma-adamantinomatous . website. Accessed October 26th, 2020.
Definition / general
  • Adamantinomatous craniopharyngioma: suprasellar or sellar epithelial neoplasm resembling ameloblastoma
Essential features
  • Always WHO Grade I
  • Tumor with palisading epithelium, "wet" keratin and stellate reticulum associated with surrounding gliosis and Rosenthal fibers
  • Epithelial neoplasm resembling ameloblastoma or keratinizing and calcifying odontogenic cyst
  • Incidence: low
  • Age: bimodal with peaks at 5 - 10 years and 50 - 60 years
    • More common than papillary craniopharyngioma (even in adults)
  • Higher frequency in Africans and Far East Asians
  • Suprasellar: frequently extend into neighboring structures
  • Rarely intranasal, sphenoid sinus, cerebellopontine angle and pineal region
  • Possible origin in remnants of Rathke pouch epithelium
  • Misplaced odontogenic rests along pituitary stalk
Clinical features
  • Insidious, with a delay of approximately 1 - 2 years between initial symptoms and diagnosis
  • Visual disturbances
  • Endocrine deficiencies
    • GH > LH / FSH > ACTH > TSH
    • Growth failure and delayed puberty in children
    • Diabetes insipidus (> adults)
  • Headache (most common, due to mass effect or hydrocephalus)
  • Large tumors in adults cause psychiatric and cognitive symptoms
  • Rare chemical meningitis with cyst rupture and spillage
  • Best diagnostic clue is preoperative imaging
  • Usually extra-axial and suprasellar
  • Multilobulated and multicystic lesions
  • Variable in size, often > 5 cm
  • Recurrences may be massive
  • MRI:
    • High signal intensity on T1 weighted images
    • Heterogeneous enhancement
    • Fluid levels consistent with cystic components
  • CT:
    • Better than MRI at showing calcifications
      Same for both types of craniopharyngiomas
    • Full pituitary endocrine workup is usually mandatory
    • Visual acuity and visual field assessment is also performed to show any deficits and rule out papilledema
    Radiology description
    • MRI without contrast
      • T1 weighted images: cystic component is often hyperintense and the solid component is isointense with enhancement of the rim or tumor nodule
      • T2 weighted images: the cystic and solid components are hyperintense
    • CT:
      • 90% are at least partially cystic
      • 90% have calcifications
      • 90% have nodular or rim enhancement
      • Tumors are heterogeneous, with the cystic component being hypodense and the solid component being isodense or slightly hyperdense with variable enhancement
    Prognostic factors
    • 5 year survival excellent
    • Patients may be left with variable endocrinologic deficiencies
    • Cystic recurrence common after incomplete excision
    • Very rare malignant transformation
    Case reports
    • Gross total excision or subtotal resection followed by radiation therapy
    • Anatomic location, size, invasion of the nearby structures and the nature of the tumor determine surgical approach
    • Most common indication for surgery is neurologic compromise from tumor mass effect
    • In children, hypothalamic and endocrine dysfunction may develop before visual defects are noticed
    • Radiotherapy is indicated for treatment of residual tumor or recurrence
    • Occasionally intralesional radiation to control cysts
    • Asymptomatic patients or very small tumors may be monitored with serial MRIs
    • Cyst aspiration combined with intracavitary phosphorus-32 (32P) instillation is an alternative to traditional surgical resection
    • Intracystic chemotherapy with bleomycin has also been tried, with some success in short term reduction of cyst size
    Clinical images

    Images hosted on other servers:

    Image A: Axial brain MRI showing a
    suprasellar mass with enhanced solid
    and multiseptated cystic components

    Gross description
    • Lobular and cystic tumor with calcifications
      • Cysts with dark "motor oil" fluid composed of cholesterol and hemorrhage
    • Irregular tumor interface with adjacent brain
    • Can be densely adherent to brain
    Gross images

    Images hosted on other servers:

    Autopsy image

    Microscopic (histologic) description
    • May appear well circumscribed
    • Microscopic brain invasion common with tongues of tumor extending into hypothalamic parenchyma
    • Compact sheets, nodules and trabeculae of squamous epithelium
    • Peripheral cells show nuclear palisading
    • Peripheral cells surround looser plumper cells called "stellate reticulum"
    • Nodules of plump, anucleate squames ("ghost" cells) and "wet" keratin
    • Intralobular whorl-like formations
    • Degenerative changes with cystic degeneration, calcifications and xanthogranulomatous reactions with giant cells
    • Piloid gliosis and Rosenthal fibers in adjacent brain
    • Rarely, melanin pigment
    Microscopic (histologic) images

    Contributed by Nelli S. Lakis, M.D., M.Sc.
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    Cytology description
    • Cohesive clumps of well differentiated squamous epithelium
    • Nodules of anucleate squames
    • Macrophages, amorphous debris and calcifications
    Positive stains
    Negative stains
    • Most cases are negative for mutant BRAF (V600E)
    Molecular / cytogenetics description
    • Activating mutations of the WNT pathway gene CTNNB1 encoding β-catenin in almost all cases
    Differential diagnosis
    • Epidermoid cyst: uniloculate with thin layer of keratinizing squamous epithelium and keratohyaline granules
    • Papillary craniopharyngioma: no palisading, no "wet" keratin, no calcifications, no "motor oil" cystic fluid, no xanthogranulomatous reaction
    • Pilocytic astrocytoma: much greater cellularity than piloid gliosis, biphasic and may have eosinophilic granular bodies
    • Rathke cleft cyst with squamous metaplasia: intrasellar, squamous epithelium as well as ciliated or mucus containing cells, no wet keratin, no calcifications, β-catenin negative nuclei
    • Xanthogranuloma of sellar region: sellar region cholesterol clefts, lymphoplasmacytic infiltrates, marked hemosiderin deposits, fibrosis, multinucleated giant cells around cholesterol clefts, eosinophilic granular necrotic debris and accumulation of macrophages, no true epithelium and may be associated with Rathke cleft cyst leakage / rupture / hemorrhage (Brain Pathol 2017 Feb 25 [Epub ahead of print])
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