NQ-028a Answer: (C) Cerebellum

NQ-028b Answer: (D) This is a heterotopia

Diagnosis: Heterotopia of cerebellar folia in cerebellar white matter

Neuroantomical considerations: You can clearly see the cerebellar folia at one corner (black arrow) and a corner of the deep gray area, likely the dentate, on the opposite corner (white arrow). Therefore, this image is taken from the cerebellar white matter in between the cerebellar folia and deep gray nuclei.

Pathology of this case: This case was an incidental finding on an autopsy brain without any neurological history or manifestation.

The structure being considered is well-defined and egg-shaped. It is composed of alternating bands of densely packed cells reminiscent of the internal granular layer and thicker bands of neuropils with the consistency of the cerebellar molecular layer. Compare this with the molecular layer at the corner of this image. There seems to be some larger cells corresponding to the Purkinje cells in this image but the magnification is too low to tell.

This image raises the possibility of a tangential cut of cerebellar folia but the alternating bands of molecular layer like tissue and internal granular layer like tissue is too irregular and there is no white matter in between. This location is also too deep for a tangential cut as it is located in the deep white matter between the deep gray cerebellar nuclei and the cortex. Therefore, this is a heterotopia of cerebellar folia in white matter.

Subependymoma: Although subependymoma is often seen in the cerebellum, there is no histologic evidence to support a diagnosis.

Open with full screen/ Open with ImageScope

Click on the icon to see an online slide of an subependymoma. Username: ouguest     Password: guestou

Ganglioglioma: There is no histologic evidence even at this magnification to suggest a ganglioglioma.

Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos): This entity is characterized by a hamartomatous like neoplastic change involving the cerebellar folia with overall preservation of the gross morphology of the cerebellar. The histologic architecture is best described as an inside out pattern. In this particular case, the folia is intact and the normal relationship between the molecular layer and the internal granular layer is maintained.