An autopsy case of superficial siderosis of the central nervous system accompanied by anterior sacral polycystic meningocele in neurofibromatosis type 1.

A 74-year-old female patient, who was diagnosed with neurofibromatosis type 1 (NF1) at the age of 40, was admitted with complaints of flickering vision and gait disturbance for the last 2 years. On admission, neurological examination revealed mild bilateral hearing loss and ataxia in the limb and trunk. Laboratory tests revealed anti-hepatitis C virus (HCV) antibody positivity and elevated HCV RNA by real-time polymerase chain reaction. The cerebrospinal fluid examination revealed a slightly yellowish appearance with elevated total protein levels. Gradient echo T2*-weighted brain magnetic resonance imaging (MRI) demonstrated a rim of hypointense lesions surrounding the surface of the cerebellum, brainstem, frontal and temporal lobes, and thalamus, which was considered as hemosiderin depositions. From these MRI findings, she was diagnosed as having superficial siderosis of the central nervous system. Cerebral angiography revealed an aneurysm-like dilatation at the bifurcation of the right internal carotid-posterior communicating artery. (99m)Tc-ethyl cysteinate dimer single-photon emission computed tomography revealed hypoperfusion in the bilateral frontal and temporal lobes. Pelvic plain X-ray, pelvic computed tomography, and lumbosacral MRI revealed a sacral defect and an anterior sacral polycystic meningocele communicating with the spinal subarachnoid space. The patient's symptoms gradually worsened, and she died of septic shock because of pyelonephritis at the age of 77. An autopsy was performed; on pathological examination, we did not observe any findings associated with rupture of the aneurysm-like dilatation in the bifurcation of the right internal carotid-posterior communicating artery and cerebral amyloid angiopathy. Because duropathies-a new neurological disease concept-have been implicated as a cause of bleeding in the superficial siderosis, the anterior sacral polycystic meningocele, a type of duropathies, was presumed to be the most probable bleeding source of the superficial siderosis in this patient. Bleeding from the meningocele might result from the vulnerability of vessel walls in NF1.