Histopathological Subtypes of Medulloblastoma According to WHO Classification (2007): An 8-year Retrospective Study

Abstract

Objective: To provide histopathological subtypes of medulloblastomas (according to 2007 WHO Classification of tumors of the central nervous system) that were previously diagnosed during 1998 to 2005 in Siriraj Hospital, and to characterize the immunophenotypic patterns of medulloblastomas in correlation with these subtypes.

Methods: All diagnosed medulloblastomas collected during 1998 to 2005 in the Department of Pathology, Siriraj Hospital were reviewed and classified according to WHO classification (2007) by H&E staining. Furthermore, we performed immunohistochemical studies, including synaptophysin, glial fibrillary acidic protein (GFAP), neurofilament, and Ki-67 to characterize the immunophenotypical patterns of medulloblastoma correlated with morphological variants. Statistic analyses were Tukey HSD, Mann-Whitney test, and Fisher’s exact test.

Results: Of 41 medulloblastomas, 32 cases were classic type (78.05%), 6 cases were large cell/anaplastic variant (14.63%), and 3 cases were desmoplastic variant (7.32%). This study showed significantly increased Ki-67 indices in the large cell/ anaplastic variant compared to either classic medulloblastoma or desmoplastic/nodular variant (p <0.05). There is no statistical difference in immunophenotypes of synaptophysin, GFAP, or neurofilament between each subtype.

Conclusion: According to 2007 WHO classification of tumor of the central nervous system 2007, in our study, the majority was medulloblastoma classic type, followed by large cell/anaplastic and desmoplastic/nodular variants, respectively. Statistical significance of Ki-67 indices suggests its applicable adjuvant diagnostic tool to distinguish the large cell/anaplastic variant from others.

Objective: To provide histopathological subtypes of medulloblastomas (according to 2007 WHO Classification of tumors of the central nervous system) that were previously diagnosed during 1998 to 2005 in Siriraj Hospital, and to characterize the immunophenotypic patterns of medulloblastomas in correlation with these subtypes. Methods: All diagnosed medulloblastomas collected during 1998 to 2005 in the Department of Pathology, Siriraj Hospital were reviewed and classified according to WHO classification (2007) by H&E staining. Furthermore, we performed immunohistochemical studies, including synaptophysin, glial fibrillary acidic protein (GFAP), neurofilament, and Ki-67 to characterize the immunophenotypical patterns of medulloblastoma correlated with morphological variants. Statistic analyses were Tukey HSD, Mann-Whitney test, and Fisher’s exact test. Results: Of 41 medulloblastomas, 32 cases were classic type (78.05%), 6 cases were large cell/anaplastic variant (14.63%), and 3 cases were desmoplastic variant (7.32%). This study showed significantly increased Ki-67 indices in the large cell/ anaplastic variant compared to either classic medulloblastoma or desmoplastic/nodular variant (p <0.05). There is no statistical difference in immunophenotypes of synaptophysin, GFAP, or neurofilament between each subtype. Conclusion: According to 2007 WHO classification of tumor of the central nervous system 2007, in our study, the majority was medulloblastoma classic type, followed by large cell/anaplastic and desmoplastic/nodular variants, respectively. Statistical significance of Ki-67 indices suggests its applicable adjuvant diagnostic tool to distinguish the large cell/anaplastic variant from others.