Meningocerebral angiodysplasia with metanephric induction failure: Broadening the spectrum of an emerging maldevelopmental syndrome

The uncommon simultaneous occurrence of an exuberant, angioma-like proliferation of superficial cerebral microvessels along with absence of the kidneys has been proposed to constitute a syndromic complex for which the term "meningocerebral angiodysplasia (or angiomatosis) with renal agenesis" (MCA-RA) is being descriptively used. We observed this constellation in one of a pair of dichorionic male twins following postpartal death in the 38th week of pregnancy. General autopsy revealed rudimentary metanephric anlagen made up of few residual glomeruli, cysts lined by flattened tubular epithelium, and islands of cartilage - corresponding to renal aplastic dysplasia. Largely inconspicuous with respect to its gyral pattern, as well as the configuration of the ventricular system, the brain microscopically showed extensive replacement of the cortex by a lattice of proliferating capillaries with necrosis of the intervening parenchyma. Minute foci of calcified necrosis were scattered in the deep subcortical white matter as well, while the ventricular ependyma and the subventricular germ cell layer remained remarkably intact. The cerebellum and brain stem appeared unaffected as well. Karyotyping of skin fibroblasts indicated a normal chromosome set of 46XY without gross structural anomalies. We interpret these findings as ones apt to being reasonably accommodated within the spectrum of MCA-RA. Although exceedingly rare, accurate identification of individual cases of MCA-RA is relevant both to differential diagnosis from its prognostically different look-alike "proliferative vasculopathy and hydranencephaly-hydrocephaly" (PVHH), and to refine the nosology of unconventional pediatric vascular malformations, for which the rather nonspecific label "angiodysgenetic necrotizing encephalopathy" is still commonly used.