Normal Cerebellar Metabolism in a Patient with Superficial Siderosis

cc This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. JMD Dear Editor, In many cases with hereditary and non-hereditary cerebellar ataxia, cerebellar dysfunctions, even in the early phase, are observed in the resting state. It has been also hypothesized in patients with superficial siderosis that accumulated hemosiderin-induced parenchymal damage in the cerebellum may lead to reduced neuronal metabolism, resulting in functional deterioration of the cerebellum. However, there are no data about the regional cerebral metabolism and perfusion reflecting neuro-nal activity in superficial siderosis. Here, we report a case of superficial siderosis that had the typical findings of the disease and the results of positron emission tomography (PET) using 18 F-fluorodeoxyglucose (FDG). A 66-year-old woman complained of a 4-year history of a slow progressive unsteadiness of gait and hearing difficulty. The patient also had subjective forgetfulness and depressive mood. There was no family history of similar symptom and no prior history of head trauma, intradural surgery, neck or backache , bladder disturbance, stroke or transient ischemic attack. On examination, her gait was markedly ataxic, with a tendency to fall. There was no eye movement limitation or other cranial nerve involvement, except for bilateral hearing impairments. There were no extrapyramidal signs, such as bradykinesia, rigidity or dystonia. Tendon reflexes were hyper-reactive, and the Babinski sign was elicited on the right side. The patient scored 32/100 on the international cooperative ataxia rating scale (postural and gait disturbance 20/34, limb ataxia 12/52). The results of our routine investigations, including hematologi-cal and biochemical screening, thyroid function test, levels of vitamin B12 and folic acid, tests for antinuclear factor, HIV and VDRL and measurements of the serum ceruloplasmin and copper levels, were normal. Serum iron was decreased to 39 mcg/dL (normal 50–150), and serum ferritin levels were elevated to 166.8 ng/mL (normal 13–150). Magnetic resonance imaging (MRI) of the brain showed marginal hypointensity involving the brain stem, cerebellum and upper cervical cord in T2-weighted images (Figure 1A). Spine MRI also demonstrated hypointensity along the superficial surface of the whole spinal cord on T2-weighted images (Figure 1B). An intracranial angiography showed no aneurysms or vascular malformations, and a brain PET using FDG showed no definite regional metabolic abnormalities of the cerebellum (Figure 1C). Cognitive evaluations, including the Seoul …