Department of Pathology, University of Oklahoma Health Sciences Center

NeuroTest Question #61 Next question Previous question

Answer: Desmoplastic infantile ganglioglioma (DIG) (B).  Level of difficulty: 4 NeuroTest NeuroLearn NeuroHelp

       Click thumbnails to see picture.

• At medium magnification (Panel A), the tumor contains islands of large cells in a fibrillary background with cells that contain smaller nuclei. The fibrillary component appears coarse and collagenous like. This desmoplastic component is better appreciated under the microscope then on computer screen. On high-magnification (Panel B), the large cells appear to be ganglionic cells featured by large purplish cytoplasm and large nuclei with prominent nucleoli.
• On Masson's trichrome, the desmoplastic component stains blue while the ganglionic cells have a pinkish cytoplasm (Panel C). In general, brain parenchymal tissue has a slightly pinkish appearance in Masson's trichrome stain and allows good separation from collagenous, fibrous component which will stain blue. The leptomeningeal is extensively involved by the tumor (Panel D) and is well demonstrated by the Masson's trichrome stain here. Mitotic figures, endothelial proliferation, necrosis are not found. On reticulin stain, deposition of reticulin around individual tumor cells is present (Panel E).
• The ganglionic cells are strongly positive for syanptophysin (Panel F) and neurofilament proteins (Panel G) on immunohistochemistry. Both the large cells and small cells are positive for glial fibrillary acidic protein (GFAP) (Panel H). In general, the pathology is that of ganglioglioma with desmoplastic change. The diagnosis is a desmoplastic infantile ganglioglioma (DIF) which is a benign tumor (WHO grade I). It should be noticed that small cell component similar to that of primitive neuroectodermal tumor or medullablastoma may be present in DIG and is not an indication of malignancy. Due to their superficial location, they are often adhered to the dura and melanocytic colonization has been described in some rare examples [Click here to see a case of DIG with melanocytic colonization].
• Clinically, DIG often present as a large, cystic, superficially located mass with frontal parietal preference and occur in infants and young children.

Discussion:

• They are very helpful information for making diagnosis. Out of the five answers being offered, neurocytoma and subependymoma usually occur as exophytic mass that protrude into the ventricles and are uncommon in young children. The pathology is not compatible with the photos provided here. Subependymal giant cell astrocytoma may have this type of appearance on casual examination and can occur in children but the locationis wrong. They like to occur also as exophytic mass that protrude into the ventricles. Dysembryoblastic neuroepithelial tumor (DNET) can occur in this location and this age group, however, they are not desmoplastic. In contrast, DNET typically present as superficially located mucoid nodules.
• Click here to see a case of subependymoma.
• Click here to see a picture of a subependymoma giant cell astrocytoma.
• Click here to see a case of neruocytoma.

Comment: KarMing-Fung@ouhsc.edu