MR imaging of the corpus callosum in pediatric patients with neurofibromatosis type 1.

BACKGROUND AND PURPOSE: Many pediatric patients with neurofibromatosis type 1 (NF-1) have an apparent increased thickness of the corpus callosum (CC) on sagittal T1-weighted images compared with patients not affected by NF-1. In this study, we compared the surface area of the CC in children with NF-1 with that of healthy pediatric control subjects to determine if this was another common intracranial manifestation of NF-1. METHODS: Midsagittal T1-weighted MR images of 43 consecutive children with NF-1 and 43 age- and gender-matched healthy control subjects were reviewed retrospectively. The surface area of the CC and the midsagittal intracranial skull surface (MISS) area were measured five times each on all midsagittal images. A mean CC to mean midline intracranial surface area ratio (CC/MISS) was calculated for each. RESULTS: There is a statistically significant increase in the mean CC surface area in pediatric patients with NF-1 (680 mm2 +/- 98, range 509-974 mm2) compared with control subjects (573 mm2 +/- 83, range 404-797 mm2). The mean MISS is significantly increased in patients with NF-1 (16568 mm2 +/- 1161, range 14107-19394 mm2 vs 15402 mm2 +/- 1133, range 12951-17905 mm2 for control subjects). CC/MISS was also significantly increased in the patients with NF-1 relative to the control subjects (.0410 +/- .0043, range .0330-.0530 vs .0372 +/- .0043, range .0270-.0470 for control subjects). CONCLUSION: A larger midsagittal surface area of the CC is another intracranial manifestation of NF-1 that can be demonstrated by sagittal MR imaging. The etiology is unclear, but could be related to abnormal neurofibromin and Ras protein activity. Potential clinical relevance is discussed herein.

Intracranial calcifications in childhood medulloblastoma: relation to nevoid basal cell carcinoma syndrome.

BACKGROUND AND PURPOSE: Medulloblastoma is one of the most common posterior fossa tumors to occur in children. Our purpose was to document the frequency, location, and time of occurrence of intracranial calcifications in cranial CT studies of children with medulloblastoma. METHODS: We retrospectively reviewed cranial CT studies of 56 patients diagnosed with medulloblastoma from 1983 through 1997 for the presence of intracranial calcifications. The findings were compared with 159 cranial CT studies of patients who were evaluated in the emergency department (control group). Thirty-two patients with medulloblastoma without shunts were compared with 118 patients from the control group without shunts. Similarly, 24 patients with medulloblastoma with shunts were compared with 41 patients from the control group with shunts. RESULTS: Overall, three (9%) patients with medulloblastoma without shunts, four (16%) patients with medulloblastoma with shunts, and four (10%) patients from the control group with shunts had falx calcification. Only the two children carrying the diagnoses of medulloblastoma and nevoid basal cell carcinoma syndrome, however, had calcification of the falx cerebri shown on the cranial CT scans obtained during the peridiagnostic period. Both were diagnosed with medulloblastoma before the age of 3 years and later developed jaw cysts and multiple basal cell carcinomas in the radiation field. CONCLUSION: Previous studies have shown that falx calcification is a major component of nevoid basal cell carcinoma syndrome. Our two cases illustrate the importance of considering the diagnosis of nevoid basal cell carcinoma syndrome when falx calcification is present in young patients with medulloblastoma. If the concomitant diagnosis of nevoid basal cell carcinoma syndrome is made, alternative types of therapy should be sought to minimize radiation therapy sequelae.

Imaging and clinical evaluation of isolated atresia of the oval window.

BACKGROUND AND PURPOSE: Congenital causes of hearing loss in children commonly are encountered, and imaging aids in diagnosis as well as presurgical evaluation. Atresia of the oval window not associated with atresia of the external auditory canal (EAC) is a rare cause of congenital hearing loss in children. We present the clinical and imaging findings in children with isolated oval-window atresia. METHODS: Atresia of the oval window was defined as the absence of the structure with the presence of a bony plate superimposed between the vestibule and middle ear. The bony plate is within the expected region of the oval window. Using a computerized database, nine patients with isolated oval-window atresia were found. All had been evaluated with high-resolution computed tomography (HRCT) and all had medical records available for review, including audiogram results. Imaging studies were interpreted by the consensus of two pediatric neuroradiologists. RESULTS: Atresia of the oval window was documented in all cases using HRCT criteria. The most common anomalies associated with oval-window atresia were inferomedial malposition of the facial nerve (n = 8), malformed incus (n = 6), and displaced stapes (n = 2). Four patients had symmetric bilateral involvement. Hearing tests were not specific, because conductive, sensorineural, and mixed patterns were found. CONCLUSION: Anomalies of the oval window should be sought in all patients with congenital hearing loss. Associated findings, such as facial nerve aberrancy and ossicular anomalies, are important in both diagnosis and surgical planning.

Stroke after zoster ophthalmicus in a 12-year-old girl with protein C deficiency.

A 12-year-old girl who had zoster ophthalmicus 10 months earlier presented with hemiparesis and corresponding basal ganglionic infarction related to middle cerebral artery branch thrombosis ipsilateral to the zoster. Hematologic evaluation disclosed protein C deficiency. This represents the first zoster-associated stroke reported in childhood associated with protein C deficiency, with extension of the latency period between zoster and infarction, previously reported to be 6 months.

Pediatric congenital bilateral perisylvian syndrome: clinical and MRI features in 12 patients.

In 1926, Foix, Chavany and Marie described an acquired syndrome of fasciopharyngoglossomasticatory diplegia resulting from bilateral infarction of the anterior operculum. Clinical features consisted of facial diplegia, dysarthria, pseudobulbar palsy, mild to severe mental retardation, and seizures. A developmental form, similar in presentation in adults with MRI findings consisting of bilateral perisylvian cortical malformation consistent with polymicrogyria involving the sylvian fissure and opercular cortex, has been recognized; but few pediatric cases of congenital bilateral perisylvian syndrome (CBPS) have been reported. Over the past four years, we have encountered 12 cases of CBPS presenting in childhood. Age ranges were from 1 week to 11 years with a median of 2.25 years; six were less than two years of age. Seven were male and five female. Ten had bilateral perisylvian polymicrogyria on MRI; two had unilateral perisylvian schizencephaly with contralateral perisylvian polymicrogyria. Clinical manifestations included developmental delay in 7; poor palatal function in 5; hypotonia in 4; arthrogryposis in 4; hemiparesis in 3; apnea in 3; paraparesis in 2; micrognathia in 2; pectus excavatum in 2; quadriparesis in 1; and hearing loss in 1. Seizures occurred in seven (58%) and consisted of infantile spasms (n = 1), generalized tonic-clonic (n = 1), complex partial (n = 2), partial motor (n = 2; 1 with secondary generalization), and febrile convulsions (n = 1). CBPS has different manifestations in the pediatric population than in adults. CBPS is more common than previously thought, is recognizable by MRI and should be suspected clinically in any infant or child presenting with oromotor dysfunction/pseudobulbar signs and developmental delay, especially if there are associated congenital malformations. Epilepsy is not a constant feature in the pediatric presentation and is variable in type and severity.