Case of Sturge-Weber syndrome type III diagnosed during dementia examination.

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Various examinations are utilized in the differential diagnosis and treatment of dementia. It is not uncommon for these examinations to detect asymptomatic disease. In the present case, the patient was a 68-year-old woman. As an infant, she and her mother had had no major problems during the perinatal period. She had, however, suffered from mild weakness and paresthesia in her left upper and lower extremities since infancy and had been diagnosed with infantile paralysis at the time (details are unknown). She had no apparent intelligence or developmental delays and had no problems with her social life. In the past, she had been outgoing and cheerful; however, in her mid-60s, her food intake and motivation had declined. In addition, her memory loss had gradually worsened, and she would occasionally lose her way in the neighborhood. Therefore, she was suspected of having dementia and was brought to our hospital by her family. Her Mini-Mental State Examination score was 17. Brain computed tomography showed bilateral enlargement of the lower angles of the lateral cerebral ventricles, as well as significant parenchymal atrophy and calcification extending from the right temporal to the parietal lobe. T2-weighted brain magnetic resonance imaging (MRI) showed high signal intensity in the subcortical white matter and dilatation of the deep medullary veins at the same location (Fig. 1). An electroencephalogram showed a potential difference between the left and right sides (left > right), but no seizure waves were detected. There was no hemangioma on her face, and her fundus, tonometry, and visual fields were normal. She had no characteristic symptoms of dementia, such as visual hallucinations or frontal lobe dysfunction. According to the criteria of the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) and the DSM-5, she was diagnosed with a comorbidity of possible Alzheimer's disease and Sturge–Weber syndrome (SWS) type III. She was treated with donepezil; however, her cognitive functioning and activities of daily living continued to deteriorate, and she was admitted to the facility 2 years later. SWS is a rare disease characterized by facial, ipsilateral leptomeningeal, and ocular hemangiomas, and is caused by a somatic mosaic mutation in GNAQ.1 In patients with SWS, the numbers of normal cortical vessels decrease with an increase in leptomeningeal hemangiomas, which subsequently impair brain perfusion. Venous stasis causes the cortex to become hypoxic, and cortical atrophy and calcification occur gradually.1, 2 Brain MRI, and especially post-gadolinium contrast imaging and susceptibility-weighted imaging, are useful for the diagnosis and evaluation of the extent and severity of brain involvement in SWS.3 Clinical symptoms of SWS include epileptic seizures, hemiparesis, visual impairments, intellectual disabilities, and glaucoma.1 In most cases, the diagnosis is often triggered by a facial hemangioma or epileptic seizures in childhood; however, a few cases are diagnosed in middle-aged people. A previous study reported generalized convulsions at the age of 55 years that led to a diagnosis of SWS.2 Among patients with SWS, those without facial hemangioma are classified as type III, which accounts for 10% of all cases.1 Although epileptic seizures are relatively common as a neurological condition, they are not manifested in approximately 15% of cases, such as in the present case.4, 5 In addition, developmental delay and progressive mental deterioration are rarely reported in SWS type III.6 Our patient had no obvious symptoms other than hemiparesis; this delayed the detection of SWS until the presentation of dementia. In general, visuospatial impairment is not considered to appear in the early stages of Alzheimer's disease.6 However, in the present case, the patient got lost in her neighborhood during the early stage. We considered the symptom to be that of topographical disorientation, which appears in a variety of brain disorders. Notably, functional decline of the right or bilateral posterior parietal lobe causes egocentric disorientation.7 Patients with this disorientation have severe deficits in representing the relative location of objects with respect to oneself,8 and they may be lost even in familiar places. The topographical disorientation in the present case may have been due to right parietal lobe dysfunction caused by SWS. Other symptoms, such as epileptic seizures, may manifest in this patient in advanced age and with progression of dementia.9 Therefore, careful follow-up was considered necessary in this case. The patient and her family have provided informed consent for publication of this report. The authors have no conflicts of interest to declare.