Cytologic findings of medulloblastoma in crush smears

OBJECTIVE: To describe the cytologic findings of medulloblastomas on intraoperative crush preparation smears and compare them with the findings of other central nervous system tumors. STUDY DESIGN: The intraoperative crush preparation smears of 19 cases of medulloblastoma were studied (6 undifferentiated type and 13 well-differentiated type). The findings were compared with those of a control group consisting of 31 astrocytomas, 22 ependymomas, 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 malignant cells with hyperchromatic nuclei and indistinct cytoplasm. Typical Homer-Wright rosettes were seen in the well-differentiated type, but they were poorly formed in the undifferentiated type. Tumor cannibalism, target inclusions, cytoplasmic vacuoles and prominent multiple nucleoli were noticed frequently in the undifferentiated type. The control group (metastatic tumors and high grade astrocytomas) rarely showed tumor cannibalism or multiple nucleoli. CONCLUSION: Smears of the undifferentiated type of medulloblastomas frequently 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.