LAUSR

Idiopathic systemic capillary leak syndrome (ISCLS) is a rare cryptogenic disorder characterized by recurrent hemoconcentration, hypoalbuminemia, edema, and hypotension due to extravascular fluid leakage. This is the first report that details uncommon extensive leukoencephalopathy caused by ISCLS upon a neuropathological investigation. A 68-year-old female had recurrent episodes of hemoconcentration, hypoalbuminemia, and generalized edema and was diagnosed with ISCLS. After 9 years, brain magnetic resonance imaging (MRI) incidentally revealed extensive leukoencephalopathy without neurological deficits. Thorough examinations ruled out other disorders, and the cerebral involvement due to ISCLS was finally diagnosed. Three years later, she developed an acute-onset coma and status epilepticus together with hypotension and hemoconcentration, which were compatible with ISCLS recurrence. Electroencephalogram and MRI were correlated with a seizure arising from the left hemisphere. Extensive leukoencephalopathy did not show notable changes for 3 years. Although treatment for ISCLS recurrence temporally improved hemoconcentration and consciousness, consciousness worsened again by marked edema of the left hemisphere, and she died of cerebral herniation. A brain autopsy revealed straggly perivascular plasma leakage around the small vessels of the deep white matter, which supported that the leukoencephalopathy was caused by ISCLS. Widespread myelin pallor and decreased axonal density with sparse astrogliosis and microgliosis were observed in the cerebral white matter and corresponded with a chronic change in the MRI. Current radiological and pathological observations revealed that frequent perivascular leakages could cause chronic leukoencephalopathy, were linked with the development of systemic capillary leakage in ISCLS, and provided insights into the mysterious pathophysiology.