Post-treatment maturation of medulloblastoma in children: two cases and a literature review

We herein report two cases of post-treatment maturation of medulloblastoma (MB). We also conducted a literature review to summarize the clinical and pathologic features of MB maturation. From January 1992 to February 2017, 52 patients with MB underwent surgical resection followed by radiotherapy and chemotherapy. Tumor cell maturation was identified in two patients who underwent a second surgery. We conducted a systematic search of PubMed and identified six such cases. In both of our patients, the pathologic type was MB with extensive nodularity (MBEN). Both patients underwent radiotherapy and chemotherapy. The tumor differentiated to gangliocytoma in both patients. In the overall analysis that also included the six cases identified in the literature, the pathologic types were classic MB (n=1), desmoplastic/nodular MB (n=2), MBEN (n=3), and unclassified MB (n=2). MB differentiated into the following types: gangliocytoma (n=2), ganglioglioma (n=1), melanocyte (n=1), neuronal differentiation (n=2), and classic MB (n=1). Desmoplastic/nodular MB and MBEN can differentiate into less malignant cells types after radiotherapy and chemotherapy. Maturation of MB may be affected radiotherapy and chemotherapy.