Eosinophilic granuloma of bone: two case reports.

Eosinophilic granuloma (EG) is a benign, self-limiting disorder that usually involves a single bone. However, there is a growing evidence that the clinical picture of EG is protean. We report two cases with EG that showed rare presentations. Case 1: A 14-year-old girl complained of headache in the left parietal region for several days. The initial examination was normal. During the next three weeks, her headache was progressive and she noticed a tender swelling on her head. Cranial computed tomography (CT) revealed an osteolytic lesion on the left parietal bone. On magnetic resonance imaging (MRI), the lesion corresponded to a tumor that arose from the intradiploic region, and showed both extracranial and epidural extension. She underwent tumor resection and a diagnosis of EG was made on pathological examination. An immunohistochemical study with Ki-67 suggested accelerated growth of the tumor cells. Case 2: A 1.9-year-old boy suddenly complained of a pain in the back and soon had difficulty in walking without help. Several days later, he became unable to sit or walk. On examination, he had spastic paraplegia in addition to painful swelling on the back. A myelogram showed a block just below the T2 vertebra. Chest CT scanning disclosed that a tumor lying posterior to the T2 vertebra was causing marked cord compression and destruction of the posterior elements of the spine. The tumor extended at T1-T3 vertebral levels. He underwent tumor resection and recovered neurological ability. EG should be considered as a differential diagnosis for patients with osteolytic lesions who exhibit aggressive clinical features.

A case of Hirayama disease.

We report a male patient with Hirayama disease aged 13. The disease was insidiously progressive and he had severe disability of the right hand at presentation. He had muscular atrophy in the intrinsic muscles of the right hand and in the distal muscles of the right forearm. The atrophy was pronounced on the ulnar side. Cold paresis was also noticed. There was no sensory disturbance. On Electromyography, neurogenic changes were recorded in several atrophic muscles. Motor and sensory nerve conduction was normal. MR images of the spinal cord were normal when it was performed with a conventional method (i.e., without neck flexion). However, characteristic MR findings were obtained when the patient lay with maximum neck flexion. The posterior wall of the cervical dural canal was shifted anteriorly at the C3-7 vertebral level, which caused cord compression at the lower cervical spinal canal. The epidural space was crescent-shaped and showed high signal intensity on T2-weighted imaging. These clinical features are typical of Hirayama disease. Pediatrician should be aware of this disease and treat it as soon as possible in order to prevent progression of the atrophy.

Trigeminally induced startle in children with hyperekplexia.

To determine the physiological features of startle reactions in children with hereditary hyperekplexia, motor responses to auditory and trigeminal stimulation were investigated in 2 patients and 3 control subjects by means of multiple surface electromyographic recordings. The pattern of motor activation in auditory startle was similar in the two groups, although the responses in the patients were increased in terms of the extent of the responses. In the patients, nose taps elicited two separate responses in various muscles. The initial, short-latency response was often elicited in all the muscles examined. This reflex was similar to the R1 component of the electrical blink reflex. In addition, the early reflex was immediately followed by the second response, which also appeared widely and was similar to R2 of the blink reflex. Taps on the supraorbital nerve elicited multiple startle patterns consisting of these two responses, although generalization was infrequent. In the control subjects, these responses were elicited in a few muscles. In the hyperekplectic children, both the early and second responses to trigeminal stimulation were increased, in addition to the audiogenic reflex. It was suggested that enhancement of these responses occurred due to hyperexcitability in the brainstem reticular formation in our patients.

[Quantitative study of brain perfusion patterns of 99mTc-ECD SPECT in children with developmental disabilities].

The aim of this study was to investigate the relationship between developmental disabilities and brain perfusion patterns. We performed technetium-99 m-ethylcysteinate dimer (99m-Tc-ECD) single photon emission computed tomography (SPECT) in 30 children with neurological disorders using the Patlak plot method. In children without developmental disabilities, the distribution of regional cortical perfusion evolved in relation to brain maturation. At one month of age, there was a predominant uptake in the perirolandic cortex. Radionuclide uptake in both the parietal and occipital cortices became evident by three months. Uptake in the temporal and frontal cortex increased by 6 and 11 months, respectively. Brain perfusion showed a pattern similar to that of adults by two years of age at the latest. In children with developmental disabilities, developmental changes of brain perfusion were delayed compared to normally developing children. Brain SPECT is a useful tool to assess the brain maturation in children with developmental disabilities.

Cortical myoclonus in children.

Cortical myoclonus is a distinct clinical condition that can be defined electrophysiologically, and occurs in both children and adults. It is well known that patients sometimes exhibit stimulus-sensitive jerks and giant somatosensory-evoked potentials (SEPs). In contrast, imaging abnormalities are less prominent in many patients. Reports focusing on cortical myoclonus, except for epilepsia partialis continua, in childhood have been limited in Japan. One reason for this could be that Japanese pediatric neurologists are not familiar with the backaveraging technique. We describe the clinical and physiological features of cortical myoclonus in ten children. Routine EEG, EEG backaveraging, SEP measurement, CT/MRI (computed tomography/magnetic resonance imaging), and TMS (transcranial magnetic stimulation) were performed. All patients exhibited clear evidence of cortical myoclonus. In six patients, backaveraging was necessary since spikes were absent on routine EEG. A cortical source of the myoclonus was further supported by a TMS study performed on four patients. The etiologies of the myoclonus were diverse, cerebrovascular disease being the most common (three patients). Stimulus-sensitive or action-induced jerks were observed in three patients. Cortical SEPs were enlarged in one patient, and reduced or absent in six. Lesions were found on CT/MRI in nine patients, in five of whom the margin of the lesion was within, or adjacent to, the sensorimotor cortex. Complete destruction of the sensorimotor cortex was not observed. It was suggested that cortical neurons in the vicinity of a lesion, rather than in the lesion itself, play a role in the generation of focal myoclonus.