Choroid plexus tumors in infancy and childhood. Focal ependymal differentiation

1432-0533

Choroid plexus papilloma ; GFAP ; Immunoperoxidase ; Ependymal differentiation ; Infancy and childhood

Springer Online Journal Archives 1860-2000

Medicine

Summary Rubinstein and Brucher [18] tested 22 choroid plexus papillomas for the presence of glial fibrillary acidic protein (GFAP), using the immunoperoxidase technique and obtained focal positive results in nine cases, all of which were adults (19–66 years of age). They recommended performing a similar study in children with a view to determining the incidence of “ependymal differentiation”. Here we report an immunoperoxidase study of 32 cases (1 month to 14 years of age) of choroid plexus tumors in infancy and childhood tested for GFAP. Nineteen cases were classified as benign papillomas and 13 as malignant (four of which included benign areas). The most frequent site [15] was the lateral ventricle (22 cases). Next came the fourth ventricle (six cases), then the third ventricle (three cases), and lastly the pontocerebellar angle (one case). We found positive results focally in epithelial tumor cells in 11 of the 32 cases (34.3%). Nine were benign and two were maligant with areas of benign or differentiated papilloma. Positive cells were present in these areas. GFAP-positive cells were classified in two groups according to their location. Type 1 cells were located in the epithelium Some of them were small rounded in contact with the basement membrane, without reaching the surface; others were elongated and columnar, some extending into processes that reached the basement membrane or the vessel walls in the stroma of the papillae. Type 2 cells were observed in the stroma of the papillae; these were elongated and stained strongly. An interesting feature in five positive cases was the observation of nodes formed by Type 2 (stromal) cells and fibrils associated with Type 1 cells in the overlying epithelium. Our finding that glial differentiation in choroid plexus papilloma epithelial cells is as frequent in children as it had been reported to be in adults, does not support the idea of a greater capability of divergent differentiation in infancy and childhood.

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