Slide 164.Medulloblastoma, Cerebellum

A. Brief Descriptions

  1. Definition : cerebellar neoplasm composed largedly of small undifferentiated cells.

  2. Occurs predominantly in children and poor prognosis.

B. Gross Findings

  1. Midline of cerebellum of children and lateral locations more common in adults.

  2. Well-circumscribed,gray,friable.

  3. Hydrocephalus due to rapid growth of the tumor.

  4. May disseminate through CSF.

C. Micro Findings

  1. Homer Wright rosettes: cells surround small stellate areas of fibrillarity without a central lumen or blood vessel.

  2. Nodular pattern ( desmoplastic variant ): mantles of dark cells surround pale island.

  3. Closely packed cells with carrot-shaped nuclei with coarse chromatin.

D. Others:


E. References

  1. Robbins Pathologic Basis of Disease, 6th ed.  P.1348-1349.




Fig. 164-1 (LP)Nodular pattern of tumor with pale cells and dark cells.




Fig. 164-2 (LP)Mantles of dark cells surround pale island.




Fig. 164-3 (LP)Detail of pale island with some differentiation.





Fig. 164-4 (HP)Homer Wright rosettes (pseudorosette).