Is medulloblastoma the same tumor in children and adults

The appearance of medulloblastoma in adult age and the uncertainoverlapping of prognostic factors in pediatric and adult populationsstimulate the question of whether medulloblastoma is different in adults andin children. The pathologic features, proliferation potential andglial/neuronal differentiation have been investigated in 42 adultmedulloblastomas and 42 medulloblastomas of children; the quantitative datahave been compared between the two groups of age. Homer-Wright rosettes,nuclear polymorphism and histologic signs of neuronal differentiation weremore frequent in children cases; GFAP-positive tumor cells and desmoplastictype were more frequent in adult cases. The mean, median and rage of LIs,with PCNA and MIB-1 were significantly (p < 0.05) higher in adults thanin children. All cases, independently from age of the patients wereimmunoreactive with markers of neuronal commitment (class III beta tubulinisotype, MAP-2, neurofilaments). The immunoreactivity pattern suggested amore mature neuronal character in desmoplastic cases of adults than ofchildren and in classic cases of children than of adults. In conclusion,some phenotypic differences between childhood and adult medulloblastomaexist, but do not support a substantially different course of the disease.The higher proliferation potential in adult than in childhood cases isunexpected in a tumor of embryonal origin, and reduces the applicability ofCollin‘s law to medulloblastoma.