EXTERNAL HYDROCEPHALUS IN A SET OF TRIPLETS

External hydrocephalus appears to be a benign form of infantile macroc ephaly which typically resolves in the second year of life. Macrocepha ly may persist into adulthood and is closely associated with benign fa milial macrocephaly.(1) The CT findings include a prominent and widene d interhemispheric fissure, enlargement of the subarachnoid space over the frontal convexities, and prominent basal cisternae.(2) Although o bstruction of the arachnoid villae has been proposed, the etiology of the accumulation of this extra-axial fluid is unknown.(3) The followin g case study of dizygotic triplets with idiopathic external hydrocepha lus highlights the hereditary basis of the condition.