Duplication of 9P and Hyperplasia of the Choroid Plexus: A Pathologic, Radiologic, and Molecular Cytogenetics Study

Abstract

Duplication of the short arm of chromosome 9 is a rare constitutional abnormality, and the presence of pathologically confirmed hyperplasia of the choroid plexus in one of two cases, * and a choroid plexus papilloma in another, raises the possibility of a relationship between the 9p abnormality and abnormal growth of the choroid plexus. Molecular cytogenetic analysis using fluorescence in situ hybridization was used for detection of chromosome 9—derived material in various formalin-fixed choroid plexus abnormalities. Extra copies of chromosome 9—derived material was found in the hyperplastic choroid plexus and in a choroid plexus carcinoma. These findings suggest that there may be an association between duplication of chromosome 9 material and abnormal development of the choroid plexus.

Key Words:

• chromosome 9p
• choroid plexus papilloma
• choroid plexus hyperplasia
• choroid plexus carcinoma