Mesial temporal sclerosis--a late complication in four allogeneic pediatric recipients with persistent seizures after an acute episode of cyclosporine-A neurotoxicity.

Mesial temporal sclerosis (MTS) is a common finding in patients with intractable temporal lobe epilepsy (TLE). In this report, we retrospectively reviewed the neuroimaging results of four children who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT), and who developed recurrent, partial, intractable seizures following a first event caused by cyclosporine-A (CSA) neurotoxicity. Neuroradiologic findings of MTS were demonstrated in all these patients. We suggest that MTS may be a consequence of CSA neurotoxicity, which induces repeated seizures, associated with other predisposing conditions, as well as being a consequence of the underlying disease and its treatment, and of severe graft-versus-host disease (GvHD).

Severe neurologic complications after hematopoietic stem cell transplantation in children.

OBJECTIVE: To describe and evaluate the incidence and risk factors of severe neurologic events (SNE) in pediatric recipients of allogeneic or autologous hematopoietic stem cell transplantation (HSCT) for hematologic or nonhematologic diseases. METHODS: Retrospective analysis of 272 consecutive children admitted to the G. Gaslini Children's Research Institute and given HSCT (70 from unrelated donors, 115 from related donors, and 87 autologous) between June 1985 and January 2001. RESULTS: Thirty-seven children (13.6%) developed SNE after a median of 90 days (range, 5 days to 8.8 years) after HSCT. Cyclosporine A (CSA) neurotoxicity was the most frequent SNE (n = 21), followed by irradiation or chemotherapy injury (n = 7), CNS infections (n = 7), cerebrovascular events (n = 3), and immune-mediated etiology SNE (n = 2). Eleven patients (30%) died because of the neurologic complications. Type of HSCT, treatment with total body irradiation (TBI), acute graft-vs-host disease (GvHD), GvHD >grade 2, and treatment with CSA were associated with a significant increased risk of SNE. CONCLUSIONS: Severe neurologic complications are frequent (14%) among children receiving HSCT, causing 8.5% of deaths after transplant. Transplant from allogeneic donor, especially if unrelated, the development of severe acute GvHD grade >2, and the use of TBI in the preparative regimen are the main risk factors for such complications.

Medulloblastoma with extensive nodularity: a variant with favorable prognosis.

OBJECT: Some medulloblastomas (MBs) are characterized by extreme nodularity and intranodular nuclear uniformity in a fine fibrillary background. These lesions have also been designated as "cerebellar neuroblastoma." Although numerous reports have been published in which their morphological features have been investigated, only a few studies have been focused on their neuroradiological appearance, biological behavior, and response to therapy. The goal of this study was to gather more information about these lesions. METHODS: The authors present 11 cases of MB with extensive nodularity. Five patients were boys and six were girls; all but one were 24 months of age or younger at diagnosis. Magnetic resonance imaging disclosed a peculiar grapelike architecture in eight cases. Surgical tumor removal was complete in nine cases and partial in one. In the other case a biopsy sample of the tumor was obtained after a preoperative course of chemotherapy. After surgery, two children were treated with radiotherapy alone and one with craniospinal irradiation followed by systemic chemotherapy. Eight patients were treated with chemotherapy only. All the patients in the study are presently alive with a median follow up of 66 months. Eight patients (73%) are in complete remission at 35 to 156 months. Three patients treated with chemotherapy alone postsurgery relapsed; however, all underwent successful retreatment (two with craniospinal irradiation and one with further surgery plus high-dose chemotherapy) and are in complete remission. A review of the literature revealed that patients in 11 of 12 reported cases were younger than 3 years of age and that seven of eight in whom follow-up information was available were alive and well, with survival times ranging from 6 to 84 months. CONCLUSIONS: Medulloblastomas with extensive nodularity represent a variant that is characterized by: 1) occurrence in very young children; 2) a peculiar grapelike appearance on neuroimaging; and 3) an apparently favorable outcome.

Unusually prolonged survival and childhood-onset epilepsy in a case of alobar holoprosencephaly.

Alobar holoprosencephaly is one of the most severe congenital malformations of the central nervous system. Most affected infants are stillborn or have a very short life-span. The survivors can present with neonatal seizures and/or infantile spasms. We report on an unusually long-lived patient with alobar holoprosencephaly and minor facial dysmorphism, who developed generalized epilepsy during childhood.

Intracranial contrast-enhancing masses in infants with capillary haemangioma of the head and neck: intracranial capillary haemangioma?

Contrast-enhancing intracranial masses are rarely found in infants with extracranial capillary haemangiomas (CH). We aimed to assess their nature and progression in three patients undergoing CT and/or MRI. The changes in size of both extra- and intracranial lesions were recorded. In a fourth case, a single examination was obtained. All patients harboured one or two enhancing intracranial nodular, meningeal-based lesions. Diffuse leptomeningeal enhancement of the cerebellar surface was also seen in one, which disappeared at follow-up. In all but one of the cases, the intracranial lesions were on the same side as the extracranial CH. These lesions and the extracranial CH demonstrated parallel changes in size (suggesting that both represent CH) during follow-up of 1-2 years: the size of intracranial lesions and the extracranial CH decreased in two cases, whereas it was unchanged in the third. One patient had a persistent trigeminal artery, while another had cerebellar atrophy with high signal in the cortex on T2-weighted images. In some cases, extracranial CH are part of PHACE syndrome; the association with intracranial CH might represent a peculiar phenotype of this rare vascular phakomatosis. As extracranial CH are known to regress spontaneously in the majority of cases, a conservative approach is recommended also for presumed intracranial CH; surgery should be avoided unless follow-up studies demonstrate growth.

Extraventricular neurocytoma with ganglionic differentiation associated with complex partial seizures.

We report an unusual case of extraventricular ("cerebral") neurocytoma with ganglion cells located in the right temporal lobe in a 9-year-old girl with complex partial seizures and precocious puberty. CT showed a calcified mass with central cystic zones. MR imaging showed a markedly hyperintense predominately solid tumor on both T1- and T2-weighted images, without appreciable contrast enhancement. Cerebral neurocytomas are histologically benign and radical surgery is curative; they should be included in the differential diagnosis of temporal lobe tumors in children.

Segmental spinal dysgenesis: neuroradiologic findings with clinical and embryologic correlation.

BACKGROUND AND PURPOSE: Segmental spinal dysgenesis (SSD) is a rare congenital abnormality in which a segment of the spine and spinal cord fails to develop properly. Our goal was to investigate the neuroradiologic features of this condition in order to correlate our findings with the degree of residual spinal cord function, and to provide insight into the embryologic origin of this disorder. We also aimed to clarify the relationship between SSD and other entities, such as multiple vertebral segmentation defects, congenital vertebral displacement, and caudal regression syndrome (CRS). METHODS: The records of patients treated at our institutions for congenital spinal anomalies were reviewed, and 10 cases were found to satisfy the inclusion criteria for SSD. Plain radiographs were available for review in all cases. MR imaging was performed in eight patients, one of whom also underwent conventional myelography. Two other patients underwent only conventional myelography. RESULTS: Segmental vertebral anomalies involved the thoracolumbar, lumbar, or lumbosacral spine. The spinal cord at the level of the abnormality was thinned or even indiscernible, and a bulky, low-lying cord segment was present caudad to the focal abnormality in most cases. Closed spinal dysraphisms were associated in five cases, and partial sacrococcygeal agenesis in three. Renal anomalies were detected in four cases, and dextrocardia in one; all patients had a neurogenic bladder. CONCLUSION: SSD is an autonomous entity with characteristic clinical and neuroradiologic features; however, SSD and CRS probably represent two faces of a single spectrum of segmental malformations of the spine and spinal cord. The neuroradiologic picture depends on the severity of the malformation and on its segmental level along the longitudinal embryonic axis. The severity of the morphologic derangement correlates with residual spinal cord function and with severity of the clinical deficit.

Langerhans cell histiocytosis presenting as a lumbosacral intradural-extramedullary mass.

The subject of this paper is a 2-year-old child with progressive paraparesis. MRI showed a large lumbosacral intradural-extramedullary mass and the histological diagnosis was Langerhans cell histiocytosis. The histopathological and neuroradiological findings are discussed.

Cystic malformations of the posterior cranial fossa originating from a defect of the posterior membranous area. Mega cisterna magna and persisting Blake's pouch: two separate entities.

Cystic malformations of the posterior cranial fossa are all but arachnoid cysts contained within the general context of the Dandy-Walker complex and may be further classified in two groups on the basis of their embryological origin: anomalies of the anterior membranous area (AMA) and anomalies of the posterior membranous area (PMA). Whether the latter group of malformations can be regarded as separate entities is still quite controversial. The present authors give a detailed account of the various embryological stages in the formation of the posterior cranial fossa and its contents and propose the identification of two anomalies derived from a defect of the PMA: the mega cisterna magna (MCM) and the persisting Blake's pouch, a new entity with different MRI features from MCM. Criteria for their recognition are discussed, stressing the capital importance of a differential diagnosis in view of the radically different therapeutic approach.

MRI in an unusual case of congenital spinal mesenchymal proliferation.

We report a child aged 2 years presenting with delayed motor development. A thoracolumbar subcutaneous mass was noticed in the first months of life. MRI showed a low conus medullaris, confirmed the presence of the mass and detected a second solid lesion in the intradural space. Surgery confirmed that the two lesions were distinct, as on MRI. The histopathological features were in common with fibrous hamartoma of infancy, giant cell angioblastoma and the "diffuse type" of infantile fibromatosis. The presence of a low conus medullaris associated with a congenital clinical presentation suggested a disontogenetic aetiology.

Medulloblastoma in children: CT and MRI findings.

Our purpose was to determine whether medulloblastoma (MB) shows specific neuroradiological features which may be employed in differential diagnosis from other common posterior cranial fossa tumours in childhood. Preoperative MRI was performed on 20 children with MB, and preoperative CT in 17 of them. All underwent surgery and histopathological diagnosis. There was a constant relationship between high density on CT and low signal on T1-weighted images. Signal behaviour on T2-weighted images and the degree of contrast enhancement were more variable. Most tumours arose in the midline, from the cerebellar vermis, involving the fourth ventricle, but hemisphere and extra-axial neoplasms were also seen. The combination of high density on CT and low signal on T1-weighted images is highly suggestive of MB and may assist preoperative differential diagnosis from other posterior cranial fossa tumours.

Intraventricular supratentorial tumors in children.

Overall, intraventricular supratentorial tumors are rare in childhood. Classification can be based on the separation of lesions originating in intraventricular structures, such as choroid plexuses, from glial neoplasms of the ventricular wall which tend to infiltrate the ventricular cavities. Aim of the present study is to review the most common neoplasms of this region in childhood. Choroid plexus tumors (papillomas and carcinomas) and subependymal giant cell astrocytomas are dealt with, while for the other neoplasms which are rarer or more typic of other age ranges, specific reports should be consulted. Choroid plexus papillomas affect infants and are the most frequent oncological type among congenital tumors. The malignant variant (grade III-IV) is represented by the less frequent the neoplasms. The malignant variant (grade III-IV) is represented by the less frequent choroid plexus carcinoma which is markedly invasive with respect to adjacent nervous structures and has a high tendency to form metastases even at onset. Anaplastic papillomas are intermediate forms whose correct histopathology is still debated. Most frequent glial tumors are subependymal giant-cell astrocytomas. They are benign tumors (grade I) typically albeit not constantly associated to tuberous sclerosis. In this case the differentiation from subependymal nodules plays a major role. Contrast enhanced CT is fundamental in this assessment. Anaplastic variants, though rare, are well-known.

Chiari complex in children--neuroradiological diagnosis, neurosurgical treatment and proposal of a new classification (312 cases).

Chiari malformations are a group of anomalies particularly involving the hindbrain and cervical spinal cord. Since these malformations present many common features, we called them "Chiari Complex". After reviewing our 312 patients affected by different types of Chiari malformations we propose the following classification: Chiari I (30 cases): 1) This malformation may be divided in two sub-types: a) classic and b) myelencephalic forms. 2) Only three children were admitted with specific clinical symptoms and they had an occipito-cervical surgical decompression. Chiari II (276 cases): 1) Most of our patients (70%) presented with progressive hydrocephalus and they needed a CSF shunt to be inserted. 2) Seven sub-types of 4th ventricle morphology and size were identified. 3) Only 11 patients underwent a cervical decompression; in 182 children CSF shunting resulted in a good clinical outcome. Chiari III (2 cases): Chiari II signs must be associated with an occipito-cervical cephalocele. In both cases there were other severe associated CNS malformations. Chiari IV (4 cases): We propose this name for patients with myelomeningocele (MMC) and severe cerebellar hypoplasia.

Ependymomas of the posterior cranial fossa: CT and MRI findings.

We studied nine children with posterior cranial fossa ependymomas to identify specific neuroradiological features. Patients were studied preoperatively with CT and MRI; T1-, T2- and proton-density (PD)-weighted images were obtained. All children underwent surgery and a definite histopathological diagnosis was made. All the tumours grew into the fourth ventricle and caused dilatation of its upper part, which resembled a cap. All but one were separated from the vermis by a cleavage plane. In eight cases there was desmoplastic development through the foramina of the fourth ventricle, and five were heterogeneous due to necrosis and cystic change; one had a haemorrhagic area. In most cases the solid portion was isointense with grey matter on T1-weighted images, hyperintense on PD weighting, and isointense on T2-weighted images. On CT the tumour was isodense in six cases and calcification was detected in four. The presence of both desmoplastic development and a tumour/vermis cleavage plane in a posterior cranial fossa tumour isodense on CT is highly suggestive of ependymoma.

Computed tomography in maple syrup urine disease.

Maple Syrup Urine Disease (MSUD) is an inherited metabolic disorder characterized by a severe, usually lethal, neonatal course in the early stages with pseudotumor cerebri and pathologically documented increased cerebral water content. CT and MRI studies in MSUD are few and the data are overlapping. This study reports CT features before and after dietary treatment in three patients; two with classical MSUD and one with an intermediate variant of MSUD. At diagnosis, CT consistently showed evidence of abnormally high lucidity involving not only white matter, but also areas of grey matter, particularly the pallidum. Furthermore, these CT changes are present both in the acute phase of classical MSUD and in an intermediate variant of the disease. The observed abnormalities evolve favorably under dietary treatment, simultaneously with clinical and neurological improvement. It is concluded that the observed CT changes indicate a diagnosis of MSUD and are relevant findings in the neuroradiologic differential diagnosis in acutely ill newborns, in which a metabolic disease may be not immediately suspected.