Asymptomatic cerebral calcification--a previously unrecognized feature.

While investigating the radiological appearances of globus pallidus calcification in an autopsy case, cortical-pia mater calcification was detected. There was no documentation of its existence in the literature of radiology, neurology and neuropathology. To establish its incidence and clinical significance, 20 consecutive autopsy brains (15 males, 5 females, age 32-73 years, mean age 56.7) were studied with high resolution radiography and histology. Clinical records, autopsy findings, in-life plain skull films and computed tomography of the brain (if available) were reviewed. Radiologically, the calcifications appeared as 1-2 mm irregular spots or tiny pin-point opacities in the pia mater and subcortical regions, either unilaterally or bilaterally in the frontal (15 cases), temporal (15), parietal (3) and occipital lobes (1). Similar calcification was detected in 1 of the 3 in-life computed tomographic scans available. Histologically, these cortical-pia mater calcifications were extracellular amorphous calcified masses of various sizes in necrotic neural tissue, frequently associated with microscopic haemorrhage and hypoxic neuronal changes in the adjacent brain tissue. Blood vessels in the region were not hyalinized or calcified. The occurrence was not related to age. Hospital stay was less than 7 days in 14 and less than 30 days in 2; 50% of patients died within 48 hours after admission. None of the patients had records of long term cytotoxic chemotherapy, radiotherapy or central nervous system infection. Two had stroke, one had cerebellar atrophy and one mild hypercalcaemia. The high incidence of calcifications in the temporal lobes, while asymptomatic, suggests that cortical calcification may be a pointer to the aetiology of idiopathic epilepsies in the elderly.