title: WNT-activated medulloblastoma with melanotic and myogenic differentiation: Report of a rare case.
abstract: Medulloblastoma (MB) with melanotic and myogenic differentiation, previously known as melanotic medullomyoblastoma, is an extremely rare histological variant of MB showing melanocytic as well as skeletal muscle differentiation. Only 10 cases of this rare tumor have been reported in the literature to date. We report this case of a 2-year-old male child who presented with a midline cerebellar mass, which on histopathological examination showed classic MB intermixed with cells containing melanin pigment, along with rhabdomyoblasts, spindle cells and occasional strap cells, which corresponded to WNT subgroup on molecular classification. The cell of origin of this MB variant is likely to be neural crest-derived stem cells which are capable of multilineage differentiation. Significant findings from previous reports and important differential diagnoses are discussed. Documentation of these tumors is important to characterize the clinical behaviour and to identify distinct genetic features, if any.
authors: Departments of Pathology, All India Institute of Medical Sciences, New Delhi, India.
authors: Madhu
authors: M
authors: Rajeshwari
authors: Departments of Pathology, All India Institute of Medical Sciences, New Delhi, India.
authors: Aanchal
authors: A
authors: Kakkar
authors: Departments of Pathology, All India Institute of Medical Sciences, New Delhi, India.
authors: Aasma
authors: A
authors: Nalwa
authors: Departments of Pathology, All India Institute of Medical Sciences, New Delhi, India.
authors: Vaishali
authors: V
authors: Suri
authors: Departments of Pathology, All India Institute of Medical Sciences, New Delhi, India.
authors: Chitra
authors: C
authors: Sarkar
authors: Neurosurgery, All India Institute of Medical Sciences, New Delhi, India.
authors: Guru Dutta
authors: GD
authors: Satyarthee
authors: Neuroradiology, All India Institute of Medical Sciences, New Delhi, India.
authors: Ajay
authors: A
authors: Garg
authors: Departments of Pathology, All India Institute of Medical Sciences, New Delhi, India.
authors: Mehar Chand
authors: MC
authors: Sharma
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D002454:Cell Differentiation; D002528:Cerebellar Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003893:Desmin / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008527:Medulloblastoma / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology*; D008543:Melanins / Q000378:metabolism; D018008:Myogenin / Q000378:metabolism; D009379:Neoplasms, Muscle Tissue; D060449:Wnt Signaling Pathway
chemical_list: D003893:Desmin; D008543:Melanins; D018008:Myogenin
keywords: WNT; medulloblastoma; melanotic medullomyoblastoma; myogenic; pigmented