title: Craniopharyngioma arising in a Rathke's cleft cyst: case report.
abstract: Craniopharyngioma is one of the most common non-glial intracranial tumors of childhood. Its relation to Rathke's cleft cyst (RCC) is controversial, and both lesions have been hypothesized to lie on a continuum of cystic ectodermal lesions of the sellar region. The authors report on a 7-year-old boy who presented with decreased visual acuity, presumably of at least 2 years' duration, and was found to have a 5.2-cm sellar lesion with rim enhancement. Histological examination of the resected lesion showed a mixture of areas with simple RCC morphology with focal squamous metaplasia and areas with typical craniopharyngioma morphology. Immunohistochemical staining with CK20 and Ki 67 differentially highlighted the 2 morphological components. Testing for beta-catenin and BRAF mutations was negative in the craniopharyngioma component, precluding definitive molecular classification. Follow-up imaging showed minimal residual enhancement and the patient will be closely followed up with serial MRI. Given the clinical and histological findings in the case, a progressive transformation of the RCC to craniopharyngioma seems to be the most plausible explanation for the co-occurrence of the 2 lesion types in this patient. An extensive review of previously proposed theories of the relationship between craniopharyngioma and RCC is also presented.
authors.affiliation: Departments of 1 Pathology.
authors.forename: Ahmed K
authors.initials: AK
authors.lastname: Alomari
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Kelley
authors.forename: Eyiyemisi
authors.initials: E
authors.lastname: Damisah
authors.forename: Asher
authors.initials: A
authors.lastname: Marks
authors.forename: Pei
authors.initials: P
authors.lastname: Hui
authors.forename: Michael
authors.initials: M
authors.lastname: DiLuna
authors.forename: Alexander
authors.initials: A
authors.lastname: Vortmeyer
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D020863:Central Nervous System Cysts / Q000150:complications* / Q000473:pathology; D002648:Child; D003397:Craniopharyngioma / Q000737:chemistry / Q000150:complications* / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D053554:Keratin-20 / Q000032:analysis; D019394:Ki-67 Antigen / Q000032:analysis; D008279:Magnetic Resonance Imaging; D008297:Male; D010911:Pituitary Neoplasms / Q000737:chemistry / Q000150:complications* / Q000175:diagnosis* / Q000473:pathology; D014786:Vision Disorders / Q000209:etiology*
chemical_list: D014408:Biomarkers, Tumor; C507499:KRT20 protein, human; D053554:Keratin-20; D019394:Ki-67 Antigen
keywords: BRAF; CK20 = cytokeratin 20; IHC = immunohistochemistry; PCR = polymerase chain reaction; RCC = Rathke's cleft cyst; Rathke's cleft cyst; SSCP = single-strand conformation polymorphism; beta-catenin; craniopharyngioma; oncology