Intradiploic epidermoid cyst of the occipital bone

BACKGROUND: A rare case of intradiploic epidermoid cyst of the occipital bone is described and recent literature, which emphasizes the radiological evaluation and surgical treatment of this lesion is reviewed. CASE DESCRIPTION: A 56-year-old female patient complained of headache and occasional episodes of vertigo for one year. Computed tomographic scan and magnetic resonance imaging were performed. The patient underwent occipital right craniotomy followed by total removal of the cyst and its capsule. RESULT: The postoperative course was uneventful and the patient was discharged 4 days later. CONCLUSION: A review of the literature shows that intradiploic epidermoid cyst of the occipital bone is rare. Correct radiological assessment and complete excision of this lesion and its capsule provides complete recovery.     

Clinical correlates of occipital intermittent rhythmic delta activity (OIRDA) in children

PURPOSE: The clinical significance of occipital intermittent rhythmic delta activity (OIRDA) on the electroencephalogram has not been fully established. Recent studies suggest that this pattern occurs almost exclusively in children and is probably of epileptic origin in most cases. We sought to characterize the electrographic features and clinical correlates of occipital intermittent rhythmic delta activity. METHODS: A review of 697 consecutive pediatric electroencephalograms detected occipital intermittent rhythmic delta activity in 24 studies. Mean patient age was 7.96 years. RESULTS: Recent convulsions and absence seizures constituted the main indications for the study. Concomitant, independent epileptiform activity was noted in half of the cases. This activity was focal in all but one case. Conversely, in most cases of absence seizures, epileptiform activity intermixed with occipital intermittent rhythmic delta activity. Furthermore, the frequency of the occipital rhythmic discharges in studies of children with absences was generally faster (3-4 Hz) than in localization-related epilepsy (2-3 Hz). Most patients were awake when occipital intermittent rhythmic delta activity occurred. Chronic encephalopathy was seen in one child only. Analysis of neuroimaging studies in eight cases revealed no structural pathology associated with occipital intermittent rhythmic delta activity. CONCLUSIONS: Occipital intermittent rhythmic delta activity is probably an epileptiform pattern, although it is noted occasionally in encephalopathic children. Its electrographic characteristics appear to differ between localization-related epilepsy and primary generalized epilepsy, particularly absence seizures.     

Parieto-occipital encephalomalacia in neonatal hyperammonemia with ornithine transcarbamylase deficiency: A case report

Urea cycle disorders are congenital metabolic disorders that often cause episodic hyperammonemia. Neuroimaging in episodic hyperammonemia demonstrates several patterns of brain injuries, including focal lesions in the lentiform nucleus, insula, cingulate gyrus, and perirolandic fissure, as well as diffuse cerebral edema. In cases with neonatal onset of hyperammonemia, similar lesions have also been reported. We herein report a boy with severe neonatal hyperammonemia caused by ornithine transcarbamylase deficiency. He presented with parieto-occipital encephalomalacia, which resembles severe neonatal hypoglycemia on magnetic resonance imaging. This radiological finding may indicate parieto-occipital vulnerability not only to hypoglycemia but also to hyperammonemia.     

Posterior glucose hypometabolism in Lafora disease: Early and late FDG‐PET assessment

Establishing an early diagnosis of Lafora disease (LD) is often challenging. We describe two cases of LD presenting as myoclonus and tonic–clonic seizures, initially suggesting idiopathic generalized epilepsy. The subsequent course of the disease was characterized by drug‐resistant myoclonic epilepsy, cognitive decline, and visual symptoms, which oriented the diagnosis toward progressive myoclonic epilepsy and, more specifically, LD. Early in the evolution in the first case, and before histopathologic and genetic confirmation of LD in both cases, [18]Fluorodeoxyglucose positron emission tomography (FDG‐PET) revealed posterior hypometabolism, consistent with the well‐known posterior impairment in this disease. This suggests that FDG‐PET could help to differentiate LD in early stages from other progressive myoclonic epilepsies, but confirmation is required by a longitudinal study of FDG‐PET in progressive myoclonic epilepsy.     

Unilateral left prosopometamorphopsia: A neuropsychological case study

We describe a patient who suddenly developed prosopometamorphopsia after a childbirth; she claimed that the left half of well-known and unfamiliar faces looked distorted. Brain MR was normal, whereas SPECT showed hypoperfusion of the left infero-lateral occipital cortex. No visual recognition defects for objects or faces were present. In three matching tasks with half-faces (Experiment 1), chimeric faces (Experiment 2), or chimeric objects (Experiment 3), the patient was impaired only when she matched pairs of chimeric faces differing in their left half; the same results were obtained after 1 year. This is the first behavioural demonstration of selective chronic metamorphopsia for the left side of faces, and provides new insights for models of face processing.