Neonatal anterior cervical arachnoid cyst: case report and review of the literature

OBJECTIVE: Anterior cervical arachnoid cysts are rare in the pediatric population, with only 16 cases reported. We present the first case of an anterior cervical arachnoid cyst in a neonate and review the literature on pediatric cervical arachnoid cysts. CLINICAL PRESENTATION: A 16-day-old baby girl with a history of myelomeningocele repair progressively developed symptoms of upper extremity weakness over the course of 2 weeks. Magnetic resonance imaging (MRI) demonstrated a compressive arachnoid cyst extending from C2 to C7. INTERVENTION: The child was taken for posterior cervical laminoplasty and cyst fenestration. Intraoperatively, diffuse cervical arachnoiditis was noted. Rapid improvement in upper extremity paresis was noted within 24 h of surgery, and MRI confirmed decompression of the cyst. However, flaccid upper extremity paresis recurred within 2 weeks. MRI confirmed recurrence of the anterior cervical arachnoid cyst. The child was taken for a secondary fenestration and stenting of the cyst. Only partial improvement in arm function was noted by 1 month following reoperation. CONCLUSION: Arachnoid cysts can be effectively treated with surgical fenestration, shunting, and complete or partial excision. Rapid identification and treatment results in improvement in myelopathic symptoms; however, the most efficacious treatment modality remains unknown. Of the 17 cases of anterior cervical arachnoid cysts reported in the literature, 11 (65%) have had either prior myelomeningocele repair or a history of spinal trauma. Anterior cervical arachnoid cysts should be considered in the differential diagnosis of acute onset myelopathy in the pediatric population especially in cases with a history of spinal trauma or myelomeningocele repair.     

Comparison of prenatal and postnatal MRI findings in the evaluation of intrauterine CNS anomalies requiring postnatal neurosurgical treatment

Aim To assess the diagnostic capability of fetal magnetic resonance imaging (MRI) in children suspected antenatally to harbor central nervous system (CNS) defects that require immediate postnatal neurosurgical treatment. Materials and methods Between 2003 and 2005, 13 fetal MRI scans were performed in mothers suspected to have fetuses with congenital CNS defects that would require surgery soon after birth. Comparisons between antenatal and postnatal scans were made with emphasis on diagnostic accuracy of antenatal examinations. Results All mothers were scanned using heavily T2-weighted fat-saturated sequences, allowing rapid acquisitions to avoid movement artefacts. Imaging quality was satisfactory in all patients. Diagnoses made antenatally were: myelomeningocele in seven, meningocele in one, diastematomyelia in one, occipital meningocele in one, and isolated hydrocephalus in three children. Of the seven children with antenatal diagnosis of myelomeningocele, one proved to have spinal lipoma postnatally. The patient who antenatally was diagnosed with meningocele proved to have spinal lipoma postnatally. These two were early antenatal MR scans. Antenatal diagnosis of hydrocephalus was made in five of the six confirmed myelomeningocele patients, which was verified postnatally. Antenatal diagnosis of Chiari II malformation was made in all six confirmed myelomeningocele patients. The antenatal diagnoses of occipital meningo-encephalocele and isolated hydrocephalus were verified postnatally. Antenatal diagnosis of diastematomyelia was not verified postnatally. Conclusion Fetal MRI scanning is an effective, noninvasive method of assessing in-utero CNS abnormalities. The diagnostic accuracy has improved to allow prediction of clinical outcome and counseling for possible treatment, but is not perfect yet to allow counseling for termination of pregnancy. The material of this paper was presented at the 34th Annual Meeting of the International Society for Paediatric Neurosurgery, Taipei, Taiwan, 10–14 September 2006.     

Simultaneous repair of myelomeningocele and shunt insertion

Methods Simultaneous shunt placement and neural tube repair are described and compared with a concomitant series of patients with delayed shunting. Twenty-eight patients with a myelomeningocele underwent closure of neural tube defects at our Institution from 1998 to 2001. Eleven patients (Group 1) had concomitant surgery performed after birth. Group 2 (7 out of 28) included patients without hydrocephalus at birth, in Group 3 (4 out of 28) the children did not develop hydrocephalus, and Group 4 (6 out of 28) patients were born outside our hospital and referred for surgical care after birth.Discussion Simultaneous insertion of shunt and correction of a myelomeningocele do not pose an additional risk to the child and do have some advantages, facilitating healing of the back without CSF leakage and protecting the brain from the effects of progressive ventricular dilatation. Patients with a myelomeningocele born outside the hospital are prone to infectious complications.     

Successful developmental outcome in intrauterine myelomeningocele repair

Introduction Myelomeningocele (MM) is one of the forms of dysraphism. Hydrocephalus secondary to Arnold-Chiari (AC) malformation is responsible for the morbidity and mortality of the disease. The intrauterine repair of MM may reverse AC and limit hydrocephalus progression.Objective The aim of this work is to report the successful outcome of a case of intrauterine correction of MM, with favorable evolution and birth at 36 weeks of pregnancy.Case report KCMC, 19 years old, was submitted to intrauterine repair of MM at 24 weeks of gestational age after approval by the family and the Research Ethics Committee of the School of Medical Sciences-UNICAMP.Conclusion Although it is not the standard option for surgical correction, selected MM cases with early fetal diagnosis may be eligible for intrauterine repair, when there is consensus with the Research Ethics Committees and family members.     

Prenatal diagnosis and postnatal outcome of fetal intracranial hemorrhage

Background

The aim of this study was to present our experience with six cases of fetal intracranial hemorrhage (ICH) in terms of prenatal diagnostic features, and postnatal outcome.

Methods

The database of prenatal diagnosis unit was searched for antenatally diagnosed ICH cases. Maternal characteristics, ultrasound (US), and magnetic resonance imaging (MRI) findings, clinical course, and postnatal outcome were noted.

Results

We evaluated six consecutive cases of fetal ICH. One case was terminated at 24 weeks, and remaining five cases were delivered between 34 and 38 weeks. Five cases (5/6) had intraventricular, and one (1/6) had intraparenchymal hemorrhage. Hemorrhages were right sided in five cases (5/6), left sided in one case (1/6). Dilated and echogenic ventricular wall were the common US findings. No predisposing factor was detected in four of the cases, and intrauterine growth restriction was an underlying factor in two fetuses. Intrauterine progression of the hydrocephaly, and parenchymal thinning was seen in four cases (4/6). In three of four cases (3/4) with progressive grade 3–4 hemorrhage and hydrocephaly, postnatal outcome were dismal, and one case had mild neurological impairment at three months. In one case which had non-progressive mild ventriculomegaly, the lesion regressed after 4 weeks, and had normal short-term outcome

Conclusion

Fetal ICH can be accurately identified and categorized by antenatal sonography, and fetal MRI. Although intrauterine regression or normal short-term postnatal outcome is possible, the outcome is usually poor for fetuses with high grade and/or progressive lesions. Therefore, further studies assessing long-term postnatal outcome are needed     

Lumbar dermoid cysts: 3 illustrative cases and a total review of the literature of the last two decades

Spinal dermoid cysts are relatively infrequent tumors generally associated with a benign course. Here we describe three cases and analyzed the 109 cases of lumbar dermal cysts described in the literature in the last 20 years. We report a pediatric patient with a dermoid cyst posterior to a lumbar surgery for myelomeningocele repair with bad evolution; and two adult patients with the affection of the motor and autonomic function with good surgical outcomes. In approximately half of the reviewed cases, it was reported at least one complication. In fact, two cases had a fatal outcome. We discuss relevant characteristics of these lesions and those aspects probably associated with complications and bad outcomes.     

Limits of the surgically induced model of myelomeningocele in the fetal sheep

Purpose

The prevention of Chiari type II malformation (CM) is commonly used as a primary outcome for the evaluation of techniques of fetal myelomeningocele (MMC) surgery in the fetal lamb. The aim of our study was to investigate the frequency of the associated CM in the MMC fetal sheep model and to investigate the contribution of prenatal ultrasound evaluation of CM at the time of prenatal repair.

Methods

A MMC-like lesion was surgically created at 75 days of gestation in 21 fetuses performing a L1–L5 laminectomy followed by an excision of the exposed dura and a midline myelotomy. At a 90-day gestation, among the 19 alived fetuses, a conventional repair of the MMC-like lesion was performed in seven, four of whom underwent cerebral ultrasound (US) examination before the repair. Twelve fetuses remained untreated (control group). All fetuses underwent post-mortem examination (PM) at 138 days.

Results

At a 90-day gestation, CM was demonstrated by US examination in all four evaluated fetuses. At birth, CM was found in 3/6 control whether CM was absent in all alived fetuses in the prenatal repair group (n?=?4).

Conclusions

Creation of a MMC-like lesion with an additional myelotomy does not always lead to hindbrain herniation. Our study suggests that CM should be assessed by ultrasound examination at the time of the prenatal repair to demonstrate the effectiveness of new techniques for the prenatal repair of MMC.     

Surgical treatment of myelomeningocele: year 2000 hospitalization,outcome, and cost analysis in the US

Objective To review cases of surgical repair for myelomeningocele (MMC) using a large inpatient database from the year 2000. Materials and methods The Nationwide Inpatient Sample (NIS) database with 7.45 million patient admissions for 2000 was retrospectively studied for the first 5 procedure diagnosis of MMC repair (ICD-9 CM procedure code 0352) and ages of less than 1 year. Eighty-eight patient stays were identified. Patient demographic data, length of stay, immediate disposition at the time of discharge, hospital information, and total cost for the hospitalization were determined. Conclusion Myelomeningocele repair is mostly performed in large teaching institutions in small numbers. The majority gets to go home at discharge. It is surprising to note that only 35% also required VP shunt placement during the same hospitalization.     

颈脊髓脊膜膨出九例临床分析

目的 探讨颈脊髓脊膜膨出的临床表现、治疗方法 及要点. 方法 西安交通大学医学院第二附属医院和西安市儿童医院神经外科自2001年1月至2006年12月共收治9例颈脊髓脊膜膨出患者,其中1例左臂无力,8例神经功能正常.2例合并脑室稍大,1例合并脊髓纵裂,1例合并隐性骶裂.患者均行包块切除、椎管探查和(或)栓系松解术. 结果患者术后均无切口感染、脑脊液漏等并发症.随访术前神经功能正常的患者,术后未见神经症状出现.术前左臂无力患者术后恢复正常.2例合并脑室稍大的患者术后恢复正常. 结论 颈脊髓脊膜膨出临床表现特殊,MRI能显示病变的细微结构和其他脊柱畸形,治疗措施是早期手术,行病灶切除和(或)栓系松解,预后良好.     

Babies with myelomeningocele in Poland: parents’ attitudes on fetal surgery versus termination of pregnancy

Abstract Background  Recent surgical advances have resulted in fetal surgery becoming an option for children with myelomeningocele (MMC). However, there is little information about the parents’ attitudes towards such therapy. Methods  Following a lecture on the current status and problems of fetal surgery for MMC, a 12-item questionnaire was administered to 58 parents of children with MMC. Questionnaire topics included knowledge of the disease and treatment options, as well as attitudes and concerns towards fetal surgery or termination of pregnancy. Results  Following the lecture, 14 (out of 58) parents felt that knowledge of the disease would allow for abortion to be an option, while 18 were uncertain. Once informed of potential risks and benefits of fetal surgery, 34 parents had a positive or rather positive attitude towards this procedure. Conclusions  On the basis of these results, it was concluded that this population is potentially interested in the use of fetal surgery.     

以视力下降为主要表现的儿童脑积水术后分流障碍的临床研究:附五例报告

目的探讨以视力下降为主要表现的脑积水术后分流障碍患儿的临床特点、诊治方法及临床结局。方法回顾性分析2015年10月至2019年10月上海交通大学医学院附属上海儿童医学中心神经外科收治的5例以视力下降为主要表现的脑室-腹腔(V-P)分流术后分流障碍患儿(占同期收治的96例V-P分流障碍患儿的5.2%)的临床资料。既往均因脑积水于出生后6个月内行V-P分流术。此次发病的病程为2 d至2年。此次入院所有患儿均行分流管修复术,术后均予门诊随访和影像学随访评估手术结局。结果5例患儿中,2例以头痛伴急性视力下降就诊;3例以视力下降伴或不伴复视、斜视就诊。术前头颅CT结果显示,1例患儿脑室增大,4例患儿脑室未见明显增大。术前X线片显示4例为分流管断裂、1例经手术探查发现为分流管脑室端堵塞。行分流管修复术后分流管通畅。5例患儿术后随访4~49个月,术前的头痛等颅高压症状均消失,但视觉障碍均无明显改善,3例患儿存在视神经萎缩。结论以视力下降为主要表现的脑积水术后分流障碍的发病率较低,可伴有颅高压症状,且易误诊而延误治疗。头颅CT、全程X线片和眼底检查是确诊V-P分流术后分流障碍的重要检查方法。分流管修复术对术前已存在的视力下降效果不佳,应尽早明确诊断,积极手术有可能缓解或避免视力问题进一步加重。     

Postsurgical infection after myelomeningocele repair: a multivariate analysis of 60 consecutive cases

Objective

We investigate the demographic, clinical and surgical variables associated with wound and ventriculoperitoneal (VP) shunt infections in a well-defined group of patients submitted to neurosurgical myelomeningocele repair.

Methods

We analyzed the data of sixty consecutive patients with a myelomeningocele diagnosis submitted to neurosurgical repair between January 2002 and December 2005. Multiple logistic regression analysis identified clinical, demographic and neurosurgical variables that were independently associated with the occurrence of wound and VP shunt infections.

Results

Seven patients (11.7%) developed wound infections after myelomeningocele repair and two (3.3%) presented with sepsis unrelated to the neurosurgical procedures. Forty-six patients (76.7%) received a VP shunt and nine of them (19.6%) had VP shunt infection. There was a non-significant trend (p = 0.09) for a higher association between thoracic than lumbar or sacral topography and the occurrence of any type of infection. Among patients who underwent VP shunt placement, there was a non-significant trend for a higher association between VP shunt infection and thoracic topography compared to lumbar or sacral regions (adjusted OR 4.3; CI 95% 0.7–24.7; p = 0.10). Evans’ index scores higher than 70 were ten times more associated with VP shunt infection (adjusted OR 10.5; CI 95% 1.6–67.4; p = 0.01) than lower scores.

Conclusion

The thoracic topography of myelomeningocele has a trend for a higher association with infection in general and VP shunt infection. Evans’ index scores higher than 70 were independently associated with VP shunt infection.     

Endoscopic transnasal intradural repair of anterior skull base cerebrospinal fluid fistulae.

This study presents the techniques and results of endoscopic diagnosis and repair of cerebrospinal fluid (CSF) fistulae involving the anterior skull base and paranasal sinuses. DESIGN: A retrospective cohort study of all consecutive patients undergoing endoscopic repair of anterior skull base CSF fistulae. SETTING: Tertiary referral institutions. MATERIALS AND METHODS: Fifty-two patients underwent endoscopic repair of CSF fistula. Thirteen cases were traumatic in origin, 11 spontaneous not associated with meningoencephalocele and 12 with meningoencephalocele. Eleven were iatrogenic and five associated with transphenoidal pituitary surgery, two acute and three delayed following radiotherapy. The average age of patients was 43 and the male to female ratio was 2:1. A variety of techniques were used to repair the dural defect. In the majority of cases placement of a fat plug on the intracranial surface of the dura was performed. RESULTS: Forty-seven of the 52 patients had successful primary endoscopic repair of the CSF fistula and skull base defect. Five patients required a repeat procedure due to early failure of the repair. After an average follow-up of 27 months no patient has had any recurrence of leak giving a primary closure success rate of 90% and secondary closure rate of 100%. CONCLUSIONS: The endoscopic transnasal approach for repair of anterior skull base CSF fistula is a reliable technique and is now the procedure of choice for patients presenting with this problem.     

Evaluation of shunt treatment in hydrocephalus with myelomeningocele: some factors relating to mental prognosis

From 1971 to 1986, the authors experienced 64 patients of myelomeningocele. Sixty out of 64 cases (94%) had both myelomeningocele and hydrocephalus. A retrospective analysis about these hydrocephalic patients was conducted on various factors relating to intelligence. Forty-nine cases received cerebrospinal fluid diversion operation within 2 years of life, while 6 cases had ventriculo-peritoneal shunt after 7 years of age and 5 cases had no surgical treatment for hydrocephalus. Statistically the following factors were significantly related to low intelligence: 1) ventriculitis suffered within two months of life: 2) association of symptomatic Arnold-Chiari malformation, and 3) myelodysplasia at or above the L2 level. However, there was no statistically significant relationship between mental prognosis and age at initial shunt, degree of ventricular dilatation before and after shunt, numbers of shunt revision, epilepsy, or subdural hematoma after shunt. These findings suggest that hydrocephalic patients with myelomeningocele will be expected to have better mental prognosis if the hydrocephalus is well controlled by shunting and if they do not have other severe malformations of the central nervous system.     

A comparison of techniques for myelomeningocele defect closure in the neonatal period

Purpose

Numerous techniques have been described for repair of myelomeningoceles, but outcome data is scarce.

Patients and methods

A retrospective review was performed in 32 consecutive patients who underwent neonatal myelomeningocele repair and extra-dural closure to determine the influence of repair type on outcome. All procedures for myelomeningocele closure were classified into one of three groups, which included primary closure, myocutaneous flaps, and fasciocutaneous flaps.

Results

Defect size ranged from 1 to 48 cm². Primary skin closure was performed in 3 patients, fasciocutaneous flaps in 13 patients, and myocutaneous flaps in 16 patients. The overall complication rate was 18 %. No difference in the complication rates among the primary closure, myocutaneous, and fasciocutaneous flap groups was observed in our analysis. While not statistically significant, our data documents an association of fasciocutaneous flaps with postoperative complications that were not evident with primary skin closure or myocutaneous flaps (odds ratio 3.8; p?=?0.15). The occurrence of one or more complications was associated with a longer hospital stay.

Conclusions

Myocutaneous flaps provide a secure repair and should be considered for smaller myelomeningocele defects in addition to the larger defects where they are more traditionally used. We propose a tissue-based classification of closure techniques strictly for multi-institution outcome comparison that may ultimately inform clinical decision-making.     

Factors associated with the timeliness of postnatal surgical repair of spina bifida

Purpose

Clinical guidelines recommend repair of open spina bifida (SB) prenatally or within the first days of an infant’s life. We examined maternal, infant, and health care system factors associated with time-to-repair among infants with postnatal repair.

Methods

This retrospective, statewide, population-based study examined infants with SB born in Florida 1998–2007, ascertained by the Florida Birth Defects Registry. We used procedure codes from hospital discharge records to identify the first recorded myelomeningocele repair (ICD-9 CM procedure code 03.52) among infants with birth hospitalizations. Using Poisson multivariable regression, we examined time-to-repair by hydrocephalus, SB type (isolated [no other coded major birth defect] versus non-isolated), and other selected factors.

Results

Of 199 infants with a recorded birth hospitalization and coded myelomeningocele repair, 87.9 % had hydrocephalus and 19.6 % had non-isolated SB. About 76.4 % of infants had repair by day 2 of life. In adjusted analyses, infants with hydrocephalus were more likely to have timely repair (adjusted prevalence ratio (aPR) = 1.48, 95 % confidence interval (CI) 1.02–2.14) than infants without hydrocephalus. SB type was not associated with repair timing. Infants born in lower level nursery care hospitals with were less likely to have timely repairs (aPR = 0.71, 95 % CI 0.52–0.98) than those born in higher level nursery care hospitals.

Conclusions

Most infants with SB had surgical repair in the first 2 days of life. Lower level birth hospital nursery care was associated with later repairs. Prenatal diagnosis can facilitate planning for a birth hospital with higher level of nursery care, thus improving opportunities for timely repair.

     

Efficacy of adjuvant chemotherapy for patients with poor-risk medulloblastoma: a preliminary report

Recent studies have demonstrated that preoperative and postoperative factors can broadly stratify patients with medulloblastoma/primitive neuroectodermal tumors (MB/PNET) into risk groups. For children with factors that suggest poor outcome after treatment with surgery and radiotherapy, the addition of chemotherapy can improve survival. Since 1983, 26 children with poor-risk posterior fossa MB/PNET have been treated at our institution with craniospinal radiation therapy and adjuvant chemotherapy. Chemotherapy consisted of vincristine during radiotherapy and eight 6-week cycles of vincristine, cis-platinum, and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU). Twenty-five of 26 patients (96%) who have been entered on this protocol remain alive and free of disease at a median of 24 months from diagnosis (range 6 to 50 months). Twenty patients have completed all therapy and are at a median of 32 months from initial diagnosis with no evidence of disease. These patients were compared to a group of children with similar prognostic features treated at our institution between 1975 and 1983. Actuarial disease-free survival was statistically significantly better for protocol patients than for historical control subjects (p less than 0.002). This difference was most marked in patients who had received radiation therapy alone (p less than 0.0003). Actuarial 2-year disease-free survival was 96% for patients on protocol as compared to 59% for historical control patients who had been treated with radiotherapy alone. The chemotherapy given in this protocol was well tolerated. The results of this study, although preliminary, suggest that adjuvant chemotherapy is at least transiently effective in improving the rate of disease-free survival for children with poor-risk MB/PNET.     

Mirror movement associated with neural tube defects

Objective

Association of mirror movements with special kinds of neural tube defects, particularly cranial dermal sinus and cervical myelomeningocele, is extremely rare. We have tried to explain the probable pathophysiology underlying this rare condition.

Clinical presentation

Two cases are presented. Case 1: A right-handed 3-year-old boy brought to the outpatient clinic for evaluation of mirror movement had been operated on at 10 days of age to repair a cervical myelomeningocele. At examination, mirror movements were observed on both sides. Case 2: A right-handed 7-year-old boy referred for vertigo and occasional vomiting since 3 months of age. The mirror movements were present in the upper extremities, and reportedly had existed since early childhood. Brain magnetic resonance imaging disclosed the dermal sinus, tract, and midline dermoid tumor.

Conclusion

To describe a meaningful association between mirror movements and congenital abnormalities in 2 cases reported here, we propose development of an abnormality in the cervical spinal cord (case 1) and cervicomedullary junction (case 2) associated with gross anomalies in the affected areas.     

Cirugía de los tumores neurales del sacro

ObjectivesOur objective is to share our experience in neurogenic tumors of the sacral area, an uncommon disease, and assess approaches, intraoperative techniques, complications and clinical course of patients in a case series.MethodsWe conducted a retrospective analysis of 19 cases of patients with neurogenic tumors in the sacral area who were diagnosed and underwent surgery at our center. Of them, 8 were male and 11 were female. They had a mean age at diagnosis of 51 years (with an age range of 25-78 years). Six patients were asymptomatic and were diagnosed incidentally, while the majority (11 patients) presented with lumbar pain accompanied by other symptoms: pain radiating to the legs, pelvic pain, sensory alterations and loss of strength in the legs. Two patients presented with another primary symptom on diagnosis: pain in the pelvic region and in the left leg. All patients underwent a least one imaging test (MRI/CT scan). Nine patients had tumors limited to the sacrum or with subsequent spread, with surgery via the posterior route. In 6 cases, an exclusively anterior approach was employed owing to the pre-sacral location of the tumor; 4 cases required both an anterior and posterior approach.ResultsThe 6 patients who were asymptomatic at diagnosis continued to have no symptoms after surgery. In 8 patients, symptoms resolved after surgery, and at discharge 4 had pain in the lumbar region or legs, which improved in subsequent consultations. One patient had symptoms consistent with motor and sensory deficit in the right leg deriving from impairment of the external popliteal sciatic nerve. The mean follow-up period was 69 months (6-178 months). Histologically, 17 cases were classified as schwannomas, one case was classified as neurofibroma, and one case was classified as neurofibrosarcoma, which received radiotherapy. Three patients with benign histologies had further surgery for local recurrences.ConclusionsWhen selecting the approach, the large size that these tumors can reach, their relationship with structures, and their anterior or posterior spread should be taken in to account. Resecting the tumor mass as much as possible provides greater benefit to the patient, as this decreases the odds of tumor recurrence without increasing intraoperative and postoperative complications when multidisciplinary teams are also used.     

Three Cases with Cavitary Lesions in a Twin Gestation Complicated by a Single Intrauterine Fetal Demise

Three cases with cavitary lesions on the cerebral convexities in twin gestation complicated by a single intrauterine fetal demise were investigated clinicopathologically. They all exhibited profound mental retardation and severe motor disturbance due to rigidospastic tetraplegia. The co-twins were macerated. Neuropathologically, malformed lesions and destructive lesions coexisted in varying degrees according to the time in fetal life, at which insults probably occurred. The cavitary lesions were located bilaterally and symmetrically on the central, parietal and occipital region of the cerebral hemispheres, in some cases, including the frontal region. Case 1 showed an incomplete gyral pattern and porencephaly with polymicrogyria bordering the defect, thus allowing us to date the insult before the 5th fetal month. In case 2, multicystic encephalomalacia was disclosed with cortical dysgenesis exhibiting status marmoratus of the cortex. Case 3 displayed sclerotic cavitary lesions with sclerosis of the insula and a few instances of cortical dysgenesis. Based on the clinical data and pathological findings, the cavitary lesions of case3 may be dated in the third trimester of gestation. Case 2 can be considered to have sustained injuries between the times estimated for cases 1 and 3. As the pathogenesis of the congenital cavitary lesions, several concepts have been proposed: intrauterine DIC (Moore et al. 1969;Romero et al. 1984), vascular disruption (Hoyme et al. 1981;Jung et al. 1984), intrauterine infection such as cytomegalic inclusion disease (Friede et al. 1976), and hypoxia due to CO intoxication of the mother (Bank1 et al. 1967) or other cause. Though the pathological observation of our cases revealed no evidence of intrauterine DIC, renal cortic necrosis, intrauterine infection or occlusion of the intracranial vessels, long-term exposure to the dead twin might have contributed to the lesions of the liveborn co-twin.