Cytologic findings of medulloblastoma in crush smears

OBJECTIVE: To describe the cytologic findings of medulloblastomas on intrao perative crush preparation smears and compare them with the findings of oth er central nervous system tumors. STUDY DESIGN: The intraoperative crush preparation smears of 19 cases of me dulloblastoma were studied (6 undifferentiated type). The findings were com pared with those of a control group consisting of 31 astrocytomas, 22 epend ymomas, 18 oligodendrogliomas, 27 meningiomas, 17 schwannomas, 17 pituitary adenomas, 3 lymphomas, 5 hemangioblastomas, 5 chordomas and 11 metastatic tumors. RESULTS: Medulloblastomas revealed clusters and isolated small, round malig nant cells with hyperchromatic nuclei and indistinct cytoplasm. Typical Hom er-Wright rosettes were seen in the well-differentiated type, but they were poorly formed in the undifferentiated type. Tumor cannibalism, target incl usions, cytoplasmic vacuoles and prominent multiple nucleoli were noticed f requently in the undifferentiated type. The control group (metastatic tumor s and high grade astrocytomas) rarely showed tumor cannibalism or multiple nucleoli. CONCLUSION: Smears of the undifferentiated type of medulloblastomas frequen tly revealed tumor cannibalism, cytoplasmic vacuoles, target inclusions and prominent multiple nucleoli. These findings have been rarely reported. The prognosis of the undifferentiated type of medulloblastoma was poor.