Miniplaques and shapeless cerebral amyloid deposits in a case of Gerstmann-Sträussler-Scheinker's syndrome.

Multicentric plaques of typical pathomorphology have been described in two members of the well-documented German family "Sch" with Gerstmann-Sträussler-Scheinker's syndrome (GSS). The case of a third affected member with a clinical course of 10 years is now reported. In addition to multicentric plaques, small granules of prion protein (PrP) with stellate ultrastructure (miniplaques) were found in the tractus perforans and alveus of the hippocampal area. At the ultrastructural level, shapeless amyloid deposits of irregularly arranged bundles of amyloid fibrils were also observed in the same region. All amyloid precipitates apparent at the light microscopic level immunostained for PrP. These observations widen the known spectrum of amyloid plaque morphology in GSS. The multicentric plaque should still, however, be considered the diagnostic hallmark of this disease.