Aneurysms and vacuolar degeneration of cerebral arteries in late-onset acid maltase deficiency.

We present a case of late-onset acid maltase deficiency (AMD) with pronounced involvement of the liver and skeletal muscles. In addition, and in contrast to other adult cases of AMD, the case presented here shows CNS pathology with hypodense and hyperintense white matter areas on CT and MRI scans, and myelin changes ranging from focal areas of demyelination to necrosis. Neuropathologic changes seem to be related to unusual vascular pathology consisting of vacuolar degeneration of small and large arterial blood vessels. Vacuoles of varying size, partly filled with granular PAS-positive material, were found in pericytes and smooth muscle cells of arterial vessel walls. Electron microscopy revealed lysosomal and cytoplasmic free glycogen in smooth muscle cells in the intima of large cerebral arteries as well as in pericytes of arterioles and capillaries. Accumulation of glycogen locally was associated with severe cellular damage and necrosis. The formation of a great number of small aneurysms of intracerebral arteries is thought to be the result of cell damage in the vessel walls.