The familial syndrome of proliferative vasculopathy and hydranencephaly-hydrocephaly: immunocytochemical and ultrastructural evidence for endothelial proliferation.

This is the fourth report of Fowler-type hydranencephaly, or proliferative vasculopathy and hydranencephaly-hydrocephaly (PVHH), and is both the first case in Europe and the first case reported in an Asian family. A 17-week fetus showed severe arthrogryposis, pterygia and muscular hypoplasia. Massive cystic dilatation of the cerebral ventricles with thin disorganized pallium was associated with calcifications and characteristic glomeruloid vasculopathy throughout the CNS. Hydranencephaly in a previous pregnancy was demonstrated ultrasonographically at 13 weeks gestation. The glomeruloid vasculopathy, unique to this disorder, has ill-defined vascular channels, prominent reticulin network and inclusion-bearing cells which our immunocytological and ultrastructural studies suggest are endothelial cells. Aetiopathogenesis remains uncertain; previous hypothesis include congenital infection or primary neuro-ectodermal failure. Our present clinical and morphological findings suggest a primary role for the glomeruloid vasculopathy at the time of vascular invasion of the cerebral mantle during the first trimester. Previous and present case data support autosomal recessive inheritance, in contradistinction to sporadic, encephaloclastic, hydranencephaly from which PVHH can be readily differentiated by microscopic examination.