title: Medulloblastoma with multi-lineage differentiation including myogenic and melanotic elements: a case report with molecular data.
abstract: We present an unusual medulloblastoma in a 3.9-year-old boy who had a 2-week history of nausea and vertigo. MRI revealed a 5×5.5×5 cm sized tumor located in the fourth ventricle and spinal leptomeningeal dissemination. The patient was treated according to the MET-HIT 2000-BIS4 protocol but showed tumor progression after 6 months and died 9 months postoperatively. Histopathologically and immunohistochemically, the tumor showed PNET-like areas with focal anaplasia, admixed rhabdomyoblastic and pigmented elements, cartilage and bone formation, as well as areas with neurocytic and glial differentiation. Neither CTNNB1 mutation nor MYCC/MYCN amplification was detected. The combination of rhabdomyoblastic and melanotic elements in medulloblastoma is exceptionally rare. Although the histopathological features suggested a teratoid tumor, the endodermal cell lineage required for this diagnosis was not present. An atypical teratoid-rhabdoid tumor was ruled out due to the presence of the INI1-protein. Regarding the molecular profile with 1q and 17q chromosomal gains and loss of chromosome 8, this tumor could be compatible with a molecular medulloblastoma Group 3 or 4. Yet, it cannot be definitively ruled out that medulloblastomas with multi-lineage differentiation represent a distinct subgroup of medulloblastoma, and it remains to be clarified whether these tumors are associated with a distinct clinical behavior.
authors.forename: Harald
authors.initials: H
authors.lastname: Stefanits
authors.forename: Georg
authors.initials: G
authors.lastname: Ebetsberger-Dachs
authors.forename: Serge
authors.initials: S
authors.lastname: Weis
authors.forename: Christine
authors.initials: C
authors.lastname: Haberler
mesh_terms: D002454:Cell Differentiation; D019070:Cell Lineage; D002528:Cerebellar Neoplasms / Q000235:genetics / Q000473:pathology* / Q000628:therapy; D059248:Chemoradiotherapy; D002675:Child, Preschool; D003131:Combined Modality Therapy; D004247:DNA / Q000235:genetics; D005091:Exons / Q000235:genetics; D017809:Fatal Outcome; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008279:Magnetic Resonance Imaging; D008297:Male; D008527:Medulloblastoma / Q000235:genetics / Q000473:pathology* / Q000628:therapy; D008548:Melanosis / Q000473:pathology*; D019635:Neurosurgical Procedures / Q000379:methods; D016612:Paraffin Embedding; D020641:Polymorphism, Single Nucleotide; D016707:Tissue Fixation; D051176:beta Catenin / Q000235:genetics
chemical_list: C495270:CTNNB1 protein, human; D051176:beta Catenin; D004247:DNA