Hemimegalencephaly: MR imaging in five children

Hemimegalencephaly is a rare brain malformation characterized by cerebral asymmetry and cortical dysplasia. Infants with the condition present with early seizures and severe encephalopathy. Five patients were studied with computed tomography and magnetic resonance (MR) imaging. MR imaging was the most efficient diagnostic method for this rare entity. It demonstrated brain hemispheric hypertrophy with lateral ventricle dilatation, abnormal gyral pattern, and a thick cortex on the enlarged side. The images correlate well with the known pathologic data.     

Evaluation of a new low-dose digital X-ray device: first dosimetric and clinical results in children

Background. A new low-dose digital X-ray device, based on Charpak's Nobel prize-winning multiwire chamber, enables the production of images at very low doses. Objectives. To present the first dosimetric and clinical results. Materials and methods. The analysis was performed on 93 children with scoliosis and 47 undergoing pelvic radiography. The comparative study between conventional X-ray and the new technique focused on three points: (1) the dose delivered by each system (2) the diagnostic information provided by each system and (3) comparison of image quality criteria with European guidelines. Results. The mean ratio of conventional dose to that of the low-dose technique was 13.1 for the spinal examination and 18.8 for the pelvis. There was no significant difference in diagnostic information available from each modality, but there was a slight difference in quality criteria in favour of the conventional technique. Conclusion. This new device allows spectacular dose reduction, consistent with adequate clinical information. Improvements of the prototype will lead to extension of potential indications and industrial development. Received: 12 September 1997 Accepted: 24 November 1997     

Focal cortical dysplasia and hemimegalencephaly: histological and neuroimaging correlations

Background. The classification of cerebral cortical dysplasia is difficult and there are histological similarities between focal cortical dysplasia (FCD) and hemimegalencephaly. Objectives. To correlate the MR features and histological data of cortical dysplasias. Materials and methods. The MR appearances of 17 brains were examined. According to the signal intensity within the pathological area on T2-weighted (T2-W) sequences we selected two groups. Results. Group 1 comprised ten patients with high signal in the dysplastic area on T2-W images. This group included five hemimegalencephalies, three frontal quadramegalencephalies, and one gyral dysplasia. The pathological hemisphere was reduced in size in one case. The cortex was thickened in all cases on T1-weighted (T1-W) images. There was loss of delineation between white matter (WM) and grey matter (GM) in all cases on both T1-W and T2-W sequences. The differential diagnosis with tumour, neoplastic-like malformation or polymicrogyria was questionable. Group 2 comprised seven patients presenting without increased signal within the dysplastic area on T2-W images. WM and GM were of similar signal intensity in six cases, and delineation between white and grey matter was absent in all cases. There were mild abnormalities on T1-W sequences in all cases. The dysplasias were limited to a lobe in five cases and a gyrus in two cases. In all cases, depiction of the malformation was a greater diagnostic problem than the differential diagnosis. Conclusions. A constant MR sign in our series was the loss of delineation between WM and GM in the dysplastic area. This correlated well with the observed histological disorganisation. Markedly high signal within the dysplastic area seems to be related to myelin abnormalities rather than glial cell abnormalities. Received: 25 July 1997 Accepted: 9 January 1998     

Long-term follow up of 69 patients treated for optic pathway tumours before the chemotherapy era

AIM: To analyse the long-term results of conservative management with radiotherapy in patients with optic pathway tumours. DESIGN: All 69 patients were symptomatic at diagnosis and most neoplasms involved the optic chiasm and hypothalamus. RESULTS: At 10 years, overall survival and progression free survival were 83% and 65.5%, respectively. After radiotherapy, vision improved in 18 patients and remained stable in 29 other patients. Cerebrovascular complications occurred in nine of 53 patients treated with radiotherapy after a median interval of two and a half years. These complications were five times more frequent in patients with neurofibromatosis type 1 (NF1). Severe intellectual disabilities were present in 18 children, most of whom underwent irradiation at a very young age (median age, 4 years). IMPLICATIONS: Radiotherapy is a valuable treatment in terms of tumour response, visual outcome, and progression free survival. However, in young children and in patients with NF1, major sequelae are encountered and new treatment strategies should be proposed for these patients.     

Dumbbell neuroblastoma. Experience at the Gustave Roussy Institute in 38 cases treated from 1982 to 1987]

Among the 282 neuroblastomas treated at the Institut Gustave-Roussy between 1982 and 1987, 38 dumbbell forms were observed. Therapeutic approaches included: 1) An initial laminectomy in forms with neurological deficit; 2) Surgical excision of the primary tumor; 3) Preoperative chemotherapy for metastatic forms and non-metastatic forms in which primary tumors considered unresectable at diagnosis; 4) Radiation therapy on macroscopic residual disease. Twenty three of 38 children presented with a neurological deficit. A laminectomy was performed in 21 cases. Neurological recovery was good in 8 cases, partial in 5 cases and absent in 5 cases. Three patients were aggravated after the procedure. The event free survival was 76%. This high survival rate is linked with: 1) The predominantly non metastatic stages (25/38); 2) A high proportion of children under 1 year of age (25/38); 3) A high proportion of thoracic locations. Out of the 29 survivors, there were 10 cases of major neurological sequelae (34%) and 9 cases of major orthopedic sequelae (31%). The coexistence of a serious functional prognosis and an excellent vital prognosis led us to analyse the therapeutic modalities and reevaluate the necessity of routine initial neurosurgical excision by laminectomy, and using a first line chemotherapy in selected indications.     

Localized dumbbell neuroblastoma: A study of 25 cases treated between 1982 and 1987 using the same protocol

Among the 108 non-metastatic neuroblastomas treated at the Institut Gustave Roussy between 1982 and 1987, 25 dumbbell neuroblastomas were observed. Therapeutics included: 1) an initial laminectomy in forms with neurological deficit; 2) surgical excision of the primary tumor; 3) preoperative chemotherapy in children in which the primary tumor was considered as unrespectable at diagnosis and postoperative chemotherapy in cases of incomplete resection; and 4) radiation therapy on macroscopic residual disease. Fifteen out of 25 (60%) presented a neurological deficit. A laminectomy was performed in 14 cases. Neurological recovery was good in 4 cases, partial in 4 cases, and absent in 4 cases. Two patients were worse after the procedure. The event-free survival was 88%. This high survival rate is linked: 1) to the non-metastatic stage; 2) to a high proportion of children under 1 year of age (18/25) (median age = 7 months); and 3) to a high proportion of thoracic location (12/25). The high incidence of macroscopically incomplete excision (13/25) did not jeopardize the prognosis. Out of the 22 survivors, there were 8 cases of major neurological sequellae (36%) and 5 cases of major orthopedic ones (26%). The coexistence of a serious functional prognosis and an excellent vital prognosis for these patients has led us to analyse the therapeutic modalities, to re-evaluate the necessity of routine initial neurosurgical removal by laminectomy and to discuss the use of first line chemotherapy. © 1993 Wiley-Liss, Inc.     

Neonatal malignant tumors. Apropos of 75 cases]

From 1975 to 1986, 75 neonates were treated at the Institute Gustave-Roussy for a malignant solid tumor, comprising 1.7% of the overall oncopediatric population treated during the same period of time. Of these 75 patients, 47 (62%) presented with neuroblastomas, 15 (20%) with mesenchymal tumors, 9 (12%) with germ cell tumors and 4 with various other types of tumors. Treatment consisted of surgery in 63 patients, chemotherapy in 43 and radiotherapy in 18. The 5 year crude survival rate was 77%. Neuroblastomas did the best with a crude survival rate of 89%. The young age of the patients resulted in two types of problems: immediate tolerance and long term sequelae. The therapeutic regimen should take into account the good prognosis of the majority of these tumors in order to decrease delayed effects.     

X-ray findings in pulmonary tuberculosis in children and its complications]

Pulmonary tuberculosis is still a common disease in children, especially those of immigrant families. Prevention and diagnosis rest on the plain chest film which should remain the first step of the work-up. Apart from cerebromeningeal complication, CT scan is also useful for evaluating chest lesions including mediastinal lymphadenopathies and lung parenchyma involvement. CT scan combined with endoscopy ensures detection of complications including bronchogenic dissemination. With a few cases as illustrations, the role of roentgenographic investigations in the management of pediatric tuberculosis is outlined.     

Results of the LMT81 protocol, a modified LSA2L2 protocol with high dose methotrexate, on 84 children with non-B-cell (lymphoblastic) lymphoma.

From May 1981 to June 1989, 84 children with non-B-cell lymphoma (82 lymphoblastic, 1 T-cell immunoblastic, 1 unclassified diffuse lymphoma) were treated in the pediatric department of the Institut Gustave Roussy according to a protocol called LMT81, which was derived from the LSA2L2 protocol of Wollner and modified by the adjunction of 10 courses of high dose methotrexate to improve the CNS prophylaxis. No planned irradiation was performed except in cases of initial tests (2 patients) or CNS (5 patients) involvement and residual mass (2 patients). Sixty patients had mediastinal involvement; for the others, primaries were in the head and neck (7), nodes (2), (sub)cutaneous (4), bone (7), and elsewhere (2). According to Murphy's staging system, there were 2 stage I, 6 stage II, 33 stage III, and 43 stage IV. Among the stage IV patients, 41 had bone marrow involvement, 24 of them with more than 25% blast cells in bone marrow and 19 with blast cells in blood; 7 had CNS involvement. Three patients did not achieve complete remission, 4 died in remission (two measles, one post-transfusion AIDS, one unexplained definitive aplasia) and 13 relapsed at 2 to 29 months (median-13 months). Among the 77 patients without initial CNS involvement, there was only one isolated CNS relapse. With a median follow-up of 57 months (10-106 months), the event-free survival is 75% (SE 2.5) for the 84 patients with a plateau at 29 months, 73% (SE 8) for stage I and II patients, 79% (SE 4) for stage III, and 72% (SE 4) for stage IV patients. Survival was similar in each stage group. Reasons for failure of treatment, however, were different, being toxic deaths in stage II; initial therapy resistance, early relapses, and toxic deaths in stage III; and tumor failures in stage IV. In conclusion, this protocol is efficacious on T and non-T, non-B childhood lymphoma with a low incidence of CNS relapse. A future study will seek to diminish toxicity and long-term sequellae while at least maintaining the same cure rate of patients.