Tectal Plate Glioma: A Clinical and Radiologic Analysis of Progression and Management in Adults

BACKGROUND

Tectal plate gliomas (TPGs) are a heterogeneous group of uncommon brain tumors. TPGs are considered indolent and are usually managed conservatively but they have the potential to transform into higher-grade tumors. The aims of this study were to investigate the natural history of adult TPG, treatment outcomes, and overall survival.

METHODS

A retrospective cohort analysis was performed of adult patients with TPG between 1993 and 2021. Baseline clinical, radiologic, and management characteristics were collected. The primary outcome was tumor progression, defined as increasing size on radiologic assessment or new gadolinium contrast enhancement. Secondary outcomes included management and mortality.

RESULTS

Thirty-nine patients were included, of whom 23 (52.2%) were men. Median age at diagnosis was 35 years (interquartile range, 27-53). Radiologic tumor progression was observed in 8 patients (20.5%). The 10-year progression-free survival was 72.6% (95% confidence interval [CI], 0.58-0.91). The 10-year overall survival was 86.5% (95% confidence interval, 0.75-1.0). Cerebrospinal fluid diversion procedures were used in 62% of the cohort (n = 24). Seventeen patients (43.6%) underwent at least 1 endoscopic third ventriculostomy, whereas only 6 patients (15.4%) underwent at least 1 ventriculoperitoneal shunt.

CONCLUSIONS

TPG has an overall favorable clinical prognosis, although progression occurs in 1 in 5 patients. Showing accurate factors by which patients with TPG may be risk stratified should be a key area of further research. A follow-up duration of 10 years would be a reasonable window based on the radiologic progression rates in this study; however, larger cohort studies are needed to answer both questions definitively.

Gamma Knife radiosurgery for low-grade tectal gliomas

BACKGROUND

Tectal gliomas are present in a critical location that makes their surgical treatment difficult. Stereotactic radiosurgery presents an attractive noninvasive treatment option. However, tectal gliomas are also commonly associated with aqueductal obstruction and consequently hydrocephalus. This necessitates some form of CSF diversion procedure before radiosurgery. The aim of the study was to assess the efficacy and safety of Gamma Knife radiosurgery for tectal gliomas.

PATIENTS AND METHODS

Between October 2002 and May 2011, 11 patients with tectal gliomas were treated with Gamma Knife radiosurgery. Five patients had pilocytic astrocytomas and six nonpilocytic astrocytomas. Ten patients presented with hydrocephalus and underwent a CSF diversion procedure [7 V-P shunt and 3 endoscopic third ventriculostomy (ETV)]. The tumor volume ranged between 1.2-14.7 cc (median 4.5 cc). The prescription dose was 11-14 Gy (median 12 Gy).

RESULTS

Patients were followed for a median of 40 months (13-114 months). Tumor control after radiosurgery was seen in all cases. In 6/11 cases, the tumors eventually disappeared after treatment. Peritumoral edema developed in 5/11 cases at an onset of 3-6 months after treatment. Transient tumor swelling was observed in four cases. Four patients developed cysts after treatment. One of these cases required aspiration and eventually disappeared, one became smaller spontaneously, and two remained stable.

CONCLUSION

Gamma Knife radiosurgery is an effective and safe technique for treatment of tectal gliomas. Tumor shrinkage or disappearance after Gamma Knife radiosurgery may preclude the need for a shunt later on.

Interhemispheric and quadrigeminal cysts

BACKGROUND

Interhemispheric and quadrigeminal cysts are rare lesions, similar in their propensity to present in young babies and to be associated with other central nervous system malformations, such as corpus callosum agenesia, holoprosencephaly, encephalocele, and neuronal heterotopias. Recently endoscopy has become increasingly popular in the treatment of arachnoid cysts, but experience with cysts located in the interhemispheric fissure and in the quadrigeminal cistern is limited.

METHODS

This study reviews the specific anatomy of interhemispheric and quadrigeminal cysts and their relationship with the ventricular system and subarachnoid cisterns to select the most appropriated treatment. It also reviews the literature on endoscopic treatment of interhemispheric and quadrigeminal cysts.

RESULTS

Interhemispheric and quadrigeminal cysts are not homogeneous, they have different extensions toward surrounding regions. In most cases it is presented as an area of contiguity between the cyst and ventricular system and/or subarachnoid cisterns, making endoscopic treatment feasible. The success rate for endoscopic treatment is not different from that reported in large series of arachnoid cysts elsewhere.

CONCLUSIONS

Endoscopic treatment should be considered the first-line option in the treatment of such lesions, even if some complications, such as subdural collections due to thinness of the cerebral mantle or subcutaneous CSF collections due to multifactorial associated hydrocephalus, must be expected.

Prion protein (PrP) deposits in the tectum of experimental Gerstmann-Sträussler-Scheinker disease following intraocular inoculation

The abnormal misfolded isoform of prion protein (PrPd; "d" for disease) is considered as a surrogate marker for infectivity in the transmissible spongiform encephalopathies (TSEs) or prion diseases, including Creutzfeldt-Jakob disease (CJD). In this experiment, we used intraocular inoculation to study PrPd deposition in the visual system of the brain of mice infected with the Fujisaki (K.Fu) strain of Gerstmann-Sträussler-Scheinker (GSS) disease. We report here that PrPd is deposited in the superior colliculus following contralateral intraocular inoculation and thus follows neuronal connections when it spreads into the brain. Until 26 weeks postinoculation, no PrPd-specific immunostaining was observed in the brain. At 27 weeks postinoculation, PrPd targeted to the contralateral superior colliculus as delicate granular synaptic deposits located in the superficial part of this structure. As already reported, a few spongiform vacuoles were visible in the same area by conventional H and E staining. In several other sections, vacuoles were visible but no PrPd staining could be detected.

6-year-old girl with hydrocephalus

With rare exceptions, pediatric tectal gliomas have been generally reported as low-grade tumors with relatively good prognosis. The patients are usually treated conservatively to manage the signs and symptoms of obstructive hydrocephalus. We report a case of a tectal glioma in a 6-years-old girl with histological features of anaplastic mixed oligoastrocytoma that continues to progress despite chemotherapy and radiation therapy.

Quadrigeminal cyst management by cystoperitoneal shunt in a 4-year-old Persian cat

Quadrigeminal cysts represent intracranial cystic accumulations of cerebrospinal fluid within the arachnoid mater at the level of the quadrigeminal cistern. Quadrigeminal cysts are rare in cats, with only one previous report in the veterinary literature. A 4-year-old, male-neutered Persian cat was presented with a 1-year duration of initially episodic, but later progressive, obtundation and collapse. Magnetic resonance imaging of the brain revealed a quadrigeminal cyst with marked compression of the adjacent neural structures, cerebellar herniation and obstructive hydrocephalus. Cystoperitoneal shunt placement was performed after the cat became refractory to medical therapy and this resulted in return of normal neurological status. The improvement in the neurological deficits following placement of a cystoperitoneal shunt in this case appeared to be correlated with resolution of the secondary effects (in particular the obstructive hydrocephalus) rather than resolution of the quadrigeminal cyst. Cystoperitoneal shunt placement was an effective long-term treatment option for the management of the quadrigeminal cyst in this cat.

Neuroendoscopically assisted cyst-cisternal shunting for a quadrigeminal arachnoid cyst causing typical trigeminal neuralgia

A quadrigeminal cistern arachnoid cyst is a very rare cause of typical trigeminal neuralgia. A 62-year-old woman presented with right facial pain of 8 years duration. Neuroradiological findings revealed a cystic mass in the quadrigeminal region that compressed the cerebellum downward and the brainstem anteriorly and was associated with hydrocephalus. She had neuroendoscopically-assisted cyst-cisternal shunting via a small craniotomy. Postoperatively, the trigeminal neuralgia disappeared. The origin of the trigeminal neuralgia may have either been a marked distortion of the pons that caused stretching of the trigeminal nerve and irregular demyelination within the root entry zone, or there was contact between the root entry zone and a vascular structure. Neuroendoscopy is useful for treating arachnoid cysts; however, in order to safely relieve symptoms, the procedure needs to be appropriately adapted depending on the pathogenesis. In this paper, we review the literature and discuss the pathophysiology and treatment of our case.

Two-stage treatment of a tectal ganglioglioma: Endoscopic third ventriculostomy followed by surgical resection

Tumours of the quadrigeminal plate in adults are usually benign. Nevertheless, obstructive hydrocephalus due to compression of the Sylvian aqueduct is an almost invariable early finding. Whether or not direct excision is undertaken, temporary or permanent treatment of the hydrocephalus is warranted. Endoscopic third ventriculostomy is an alternative to insertion of a shunt and provides both acute and long-term relief of hydrocephalus-related symptoms. We chose a two-stage approach for treating a tectal ganglioglioma in an adult: endoscopic third ventriculostomy followed by surgical excision. The advantages and disadvantages of each therapeutic strategy are discussed.

Tectal plate cyst in adults

Tectal plate cysts are very rare. We report two adult patients with benign tectal plate cyst and secondary hydrocephalus. The first patient had an unusual eye movement disorder with bilateral upper eyelid retraction (Collier's sign), limited upgaze, severe upgaze evoked nystagmus and retraction nystagmus. The second patient presented with ataxia and failure of upward gaze. Endoscopic fenestration of the tectal plate cyst and endoscopic third ventriculostomy in both cases result in neurological improvement. To the best of our knowledge, similar lesions at this site have not been reported in adults. The differential diagnosis with arachnoid cysts of the quadrigeminal CSF cistern is discussed.

Endoscopic third ventriculostomy for tumor-related hydrocephalus in a pediatric population

OBJECT

Endoscopic third ventriculostomy (ETV) has become a common alternative for managing hydrocephalus in select patients. Nevertheless, there is still controversy regarding the indications for ETV as the primary procedure, given its variable success rates. The purpose of this study is to review the authors' experience with ETV for a variety of patients.

METHODS

A total of 43 children underwent ETV between July 1992 and June 2003. Their medical records, operative reports, and imaging studies, when available, were retrospectively reviewed with regard to outcome, complications, and patency rate. Treatment failure was defined as the need to place a shunt within 4 weeks of performing ETV in the patient. There were 20 male and 23 female patients with a mean age of 9.6 years (range 8 weeks-21 years). The overall success rate was 69.8%, and the mean follow-up duration was 24.6 months. Six patients underwent eight repeated ETVs at a mean interval of 25 months, with a patency rate of 62.5% after the second procedure. Only two surgeries were aborted for anatomical reasons. The highest success rates (100% in each instance) were achieved for obstructive hydrocephalus resulting from midbrain/tectal tumor (four patients) and pineal tumor (three patients).

CONCLUSIONS

The ETV procedure is an effective management tool for obstructive hydrocephalus in children. It should be considered the primary procedure, rather than ventriculoperitoneal shunts, in carefully selected children. The success rate is dependent on the origin of the hydrocephalus.

Fetal arachnoid cyst of the quadrigeminal cistern in MRI and ultrasound

CASE

The authors report a fetus with an arachnoid cyst of the quadrigeminal cistern without hydrocephalus at 30 gestational weeks.

DISCUSSION AND CONCLUSION

We reviewed the literature and could find only 62 reported cases of arachnoid cyst of the quadrigeminal cistern. We present a case without hydrocephalus diagnosed by combining ultrasound (US) and magnetic resonance imaging (MRI). The fetus, born by normal delivery, was followed up and did not show hydrocephalus for 1 year. This combined prenatal study, which uses US and MRI, helps in dispensing proper counseling to parents and assists the gynecologist and the neurosurgeon in the pre- and postnatal management of this condition.

Quadrigeminal cistern lipoma

Intracranial lipomas are rare benign congenital neoplasms accounting for 0.1 to 0.5% of all primary brain tumours. Approximately 50% are associated with other cerebral developmental disorders. These slow growing benign lesions are usually asymptomatic and rarely require surgery. We report the case of a 37 year old woman presented with signs of raised intracranial pressure. Computerized tomography and magnetic resonance imaging demonstrated a quadrigeminal cistern lipoma compressing the aqueduct of Sylvius. The patient underwent surgery and a distinct plane of cleavage between the lipoma and the adjacent neural structures was found, allowing total removal of the lesion. Postoperatively, the patient was relieved of her original symptoms but developed akinetic mutism which lasted for two weeks. Intracranial lipomas rarely become symptomatic and surgery is seldom required. If the lesion progresses and causes symptoms of raised intracranial pressure or compression of neural structures, surgical intervention is indicated. Total removal should not be attempted unless a plain of cleavage between the lesion and adjacent neural structures is present. Surgical manipulation should be minimised to avoid complications.

Incidental pediatric intraparenchymal xanthogranuloma: case report and review of the literature

Juvenile xanthogranuloma (JXG) is a specialized form of non-Langerhans cell histiocyte proliferation that occurs in children. The majority of cases present as a solitary cutaneous lesion with a predilection for the head and neck region; however, isolated lesions occasionally have been identified in the central nervous system. The cutaneous forms of JXG usually follow a benign course. Other physicians have reported surgery as the first line of treatment in symptomatic patients with accessible lesions. Adjuvant therapies may be indicated for multicentric or surgically inaccessible lesions. The authors describe an unusual case of isolated intraparenchymal JXG in an asymptomatic child with no cutaneous manifestations and provide a review of the literature.

[Selection of surgical approach for quadrigeminal cistern arachnoid cyst]

Preoperative magnetic resonance imaging of 4 cases of quadrigeminal cistern arachnoid cyst were retrospectively reviewed and patterns of extension to surrounding cisterns from the quadrigeminal cistern were examined. Relationship between patterns of extension to surrounding cisterns and selected surgical approach were evaluated. In 2 cases, the cyst extended anteriorly and compressed the quadrigeminal plate. These two cases had hydrocephalus due to aqueductal stenosis. The anteroirly extending cyst was treated with endoscopic ventriculocystocisternostomy via the lateral and third ventricles. In one case, the cyst extended superiorly to the velum interpositum cistern, and was treated with endoscopic ventriculocystocisternostomy via the lateral ventricle. In one case, the cyst extended laterally to the ambient cistern and compressed the posterior horn of the lateral ventricle. This case had loculated hydrocephalus of the inferior horn. The laterally extending cyst was treated with resection of the wall of the arachnoid cyst via an infratentorial supracerebellar approach assisted by endoscope. All cysts were successfully treated. Injury of the foramen of Monro occurred during a procedure using a flexible endoscope in a case with an anterior extending cyst. Exact analysis of the preoperative imaging and selection of appropriate surgical approach are key factors for successful treatment of a quadrigeminal cistern arachnoid cyst.

[Quadrigeminal cistern and calcarine fissure lipoma: case report and review of the literature]

We report the case of a multiple intracranial lipoma in a 47 year-old patient presenting with headache dizziness and quadrantanopsia. MR imaging revealed the presence of 2 lipomas, one located within the quadrigeminal cistern and the other in the calcarine fissure. To our knowledge, this combination of this rare lesion has not been yet described. We review the current literature.

Degree of tectal beaking correlates to the presence of nystagmus in children with Chiari II malformation

INTRODUCTION

Tectal beaking is a common finding in children born with a myelomeningocele. Quantitation of the presence or absence of this finding correlated with normal or abnormal eye movements is lacking in the medical literature.

MATERIALS AND METHODS

We prospectively evaluated 50 children in our multidisciplinary spina bifida clinic. Each child was observed for the presence or absence of nystagmus at rest or with extraocular movement. Grades of nystagmus and severity of tectal beaking (Types I-III) on MRI were then correlated.

RESULTS

Overwhelmingly, children with greater dysmorphology of the mesencephalic tectum were most likely to have nystagmus. Higher grades of nystagmus were associated with Type III tectal beaking.

CONCLUSIONS

We have demonstrated that there is a correlation between the presence and severity of nystagmus and the severity of tectal beaking and have quantified this association in patients with the Chiari II malformation. This information may act as a guide in predicting which children with the Chiari II malformation will have significant nystagmus. These data may aid the clinician in the interpretation of oculomotor abnormalities in this cohort of patients.

Selective and sequential therapy of oculomotor and palpebral sequelae resulting from biopsy of dorsal midbrain sarcoidosis

BACKGROUND

Biopsy of a dorsal mesencephalon lesion often leads to neuro-ophthalmological complications, namely dorsal mesencephalic syndrome, skew deviation, IV (th) palsy, or Horner's syndrome.

HISTORY AND SIGNS

A 26-year-old man underwent a biopsy of the quadrigeminal plate for a lesion which revealed to be neurosarcoidosis. Post-operative complications included a left homonymous hemianopia, a left III (rd) nucleus palsy, a bilateral IV (th) palsy and a bilateral internuclear ophthalmoplegia. Palpebral fissures were narrowed to 2 mm on both sides. In primary gaze there was 24 degrees of exotropia, 17 degrees of right hypertropia and 30 degrees of exyclorotation.

THERAPY AND OUTCOME

After 24 months of stable evolution, three oculomotor surgical procedures were performed including: surgery on both horizontal muscles of the left eye; shortening of both superior oblique muscles; resection of the right lateral rectus muscle, and posterior fixation of an inferior rectus muscle. Bilateral brow suspension on the frontal muscle of both superior eyelids was then performed. Evolution was favorable with a binocular single field of vision measuring 17 degrees horizontally and 20 degrees vertically centered on the primary gaze. Palpebral fissures measured 7 to 8 mm in primary gaze.

CONCLUSIONS

The neuro-ophthalmological sequelae which followed the biopsy of a neurosarcoidosis lesion of the quadrigeminal plate were so severe that this patient was completely handicapped. A four-step surgery correcting the horizontal, torsional, vertical components, then the bilateral ptosis allowed the patient to recover both a satisfying function and esthetical aspect.

One stage removal of periaqueductal glioma in adult via infratentorial supracerebellar and transaqueductal approaches

Most cases of periaqueductal tumours were found in children and adolescents, so treatment modalities in adults are not evaluated yet. A case of 40 years old woman with tectal and periaqueductal protoplasmatic astrocytoma grade II with history of headache and episodes of syncope is described. MRI showed triventricular hydrocephalus. After a shunt procedure she was doing well for about 15 months. Then she became somnolent, disoriented, and Parinaud syndrome appeared. The solid tumour was resected microsurgically in one stage. A part of it was removed via the supracerebellar infratentorial approach and tectal plate incision. The remainder of the tumour was removed through the fourth ventricle and the aqueduct which was filled by tumour mass. Postoperatively bilateral ptosis, vertical gaze palsy, slight horizontal gaze limitation and pupilloplegia were the main neurological sequelae. They all almost completely resolved within a year. The patient is doing well two and half years after the surgery. MRI showed patency of the aqueduct and no residual tumour. The authors suggest, that direct surgical attempt at total tumour removal should be considered in cases of periaqueductal and tectal gliomas. They also believe it is the first described case, in whom this type of tumour was totally removed by a combined transtectal and transaqueductal route.

Intracranial extramedullary hematopoiesis associated with pilocytic astrocytoma: a case report

Intracranial EMH is only occasionally found in primary brain tumors (mostly hemangioblastomas) and, to our knowledge, this is the first case of EMH associated with an astrocytoma. Intracranial extramedullary hematopoiesis (EMH) is described in a 29-year-old man with a recurrent pilocytic astrocytoma in the tectal region. Special stains confirmed the identities of erythroid, myeloid and megakaryocytic cells. The patient had no evidence of a predisposing bone marrow disorder or systemic EMH. Although the presence of multinucleated and blastic cells associated with a low-grade brain neoplasm is unusual, recognition of hematopoietic lineages allows EMH to be readily identified. Another tumor resection after a year of follow-up confirmed the absence of malignant progression in this recurrent astrocytoma. The small number of cases describing intracranial EMH in the absence of systemic hematologic abnormalities are correlated with the findings in this case. The low incidence of intracranial EMH indicates that cells with hematopoietic potential are seldom exposed to a supportive microenvironment within the central nervous system. However, intracranial EMH should be included as a potential, ancillary diagnosis when considering brain lesions. This may be particularly true if medical therapies involving growth factors or stem cells are found to promote hematopoiesis.

Tectal gliomas in children: the implications for natural history and management strategy

Tumors involving the tectal region constitute a distinct subgroup of brain stem gliomas with an indolent clinical course. Here, we present the clinical and neuroradiologic features of 9 children with tectal tumors. All patients presented with signs and symptoms of hydrocephalus and were managed with ventriculoperitoneal shunt insertion. MRI studies revealed focal hyperintense lesions on T2-weighted images without any contrast enhancement, and no evidence of progression was demonstrated in any patient. We also reviewed the published series of tectal gliomas in the literature to compare with our results. Based on these and other published series, it was concluded that intrinsic tectal gliomas of childhood with sizes less than 2 cm in diameter and without any tumor extension or contrast enhancement constitute a specific subgroup of tectal masses which rarely display invasive clinical behavior and should be managed conservatively. CSF diversion procedures and long-term yearly follow-up examinations with MRI scans are sufficient in these patients.

Dysembryoplastic neuroepithelial tumor of the midbrain tectum: a case report

Dysembryoplastic neuroepithelial tumor (DNT) is a relatively new nosologic entity. First described in 1988, it is now included in the "neuronal and mixed neuronal-glial tumours" category in the revised 2000 World Health Organization (WHO) Classification of Tumours of the Nervous System. The collective experience of more than 300 reported cases indicates that, with only rare exceptions, DNTs are cerebral cortical lesions. At present, the actual incidence of extracortical DNT is unknown. We describe, the clinicopathologic features of the first tectal DNT. The patient was a 51-year-old man with a 2-month history of pulsatile headaches. On neurologic examination, the only abnormality was gait ataxia. Magnetic resonance imaging (MRI) demonstrated a midbrain tumor involving the tectum. It was hypointense on T1-weighted images and featured an iso- to hyperintense nodule at its center. The nodule showed enhancement upon contrast administration. No aqueductal obstruction or intraventricular extension of tumor was detected. The tumor was approached supratentorially and removed completely. The mucoid tumor was well demarcated from neural tissue. Histopathologically, it was a typical DNT, exhibiting a nodular pattern of growth with a "specific glioneuronal component." This case report documents the first DNT to arise in the midbrain tectum and focuses on the problem of diagnosing this uncommon tumor at extracortical sites.

Quadrigeminal non-aneurysmal subarachnoid hemorrhage--a true variant of perimesencephalic subarachnoid hemorrhage. Case report

Spontaneous non-aneurysmal subarachnoid hemorrhage (SAH) centered in the quadrigeminal cistern has been proposed as a variant of perimesencephalic non-aneurysmal SAH (PNSH). Some authors contest the existence of this entity, claiming it results either from head trauma or an undiscovered P2-P3 aneurysm, and conclude that all PNSH arise in front of the brainstem in a 'pretruncal' location. We report a patient with a quadrigeminal pattern of subarachnoid blood who was investigated with two digital catheter angiograms, including 3-D angiography, plus a high-resolution computed tomography angiogram. No abnormal findings were present and the patient had an excellent outcome. We propose that the more common pretruncal PNSH and less common quadrigeminal PNSH are two types of perimesencephalic SAH with separate, distinct etiologies, both of which have a more benign clinical course than aneurysmal SAH.

Effects on the optokinetic system of midline lesions in the pretectum of monkeys

The nucleus of the optic tract (NOT), an important visuo-motor relay between the retina and preoculomotor structures, is responsible for mediating horizontal optokinetic nystagmus (OKN) in monkeys, cats, rabbits and rats. In addition to its projection to the vestibular nuclei, the NOT has a prominent projection to the contralateral NOT via the posterior commissure. In order to evaluate the role of the commissural fibers between the NOTs in OKN, we cut the posterior commissure in three Macaca fuscata. The animals viewed the OKN stripes under three conditions: right eye viewing, left eye viewing, and both eyes viewing. OKN was recorded in response to counter-clockwise and clockwise stimulation at stimulus velocities of 30 degrees/s, 60 degrees/s and 90 degrees/s. After control data were gathered, the posterior commissure was transected with an operating knife. Before the animal was sacrificed, biocytin, an anterograde tracer, was injected into the left NOT in order to confirm that all of the commissural fibers had been cut. Although the midline lesions decreased the initial rapid rise and steady state OKN slow-phase velocity in all three animals, there were no directional differences observed during monocular clockwise or counter-clockwise visual stimulation to either eye. In two of the three animals, there were no significant differences in the time-constants of optokinetic after nystagmus (OKAN) after the lesion. In the remaining animal, the time-constants decreased at stimulus velocities of 30 degrees/s and 60 degrees/s. In conclusion, gain reduction in the rapid rise and steady state slow-phase velocity of OKN can be explained by removal of an excitatory signal mediated by commissural fibers to inhibitory interneurons in the contralateral NOT. However, interrupting the commissural fibers had no effect on the velocity storage mechanism, because the time-constants of OKAN mostly remained largely unchanged by the lesion.

Longstanding tectal tumors: proton MR spectroscopy and diffusion MRI findings

Four patients with longstanding tectal tumors are included in this study. The tectal lesion in a neurofibromatosis type 1 (NF1) patient was due to a hamartoma, while others represented gliomas. On spectroscopy, decreased NAA peaks with resultant decreases in the NAA/Cho, and NAA/Cr ratios were observed in two patients. In three patients, on diffusion MRI the tectal tumors were hyperintense on b=1000 s/mm(2) (heavily diffusion-weighted) images. On apparent diffusion coefficient (ADC) maps, they had high signal, and high ADC values (mean=1.20 x 10(-3)mm(2)/s), compared to normal cerebral parenchyma. Diffusion MRI findings suggested that tectal tumors had a relatively high nuclear to cytoplasmic ratio (high-signal on b=1000 s/mm(2) images) in association with a relatively loose intercellular matrix (high ADC values).

Endodermal cyst of the quadrigeminal cistern: case report

BACKGROUND

Endodermal cysts usually develop in the subdural space in the anterior spinal cord and rarely occur inside the cranium. Most intracranial endodermal cysts develop in the posterior fossa. We report the first case of an endodermal cyst in the quadrigeminal cistern.

CASE DESCRIPTION

The patient was a 71-year-old man who suffered from gait disturbance for 6 months. Although head computed tomography (CT) scanning 4 years previously did not show any cystic lesion, CT and magnetic resonance imaging (MRI) on admission showed a cystic lesion extending from the quadrigeminal cistern to the right ambient cistern. The cyst was subtotally removed via a suboccipital transtentorial approach. The cyst wall consisted of a layer of columnar epithelium and connective tissue. Based on the results of immunostaining, it was diagnosed as an endodermal cyst.

CONCLUSIONS

It is possible that the increase of secretion from the cells lining the cyst may have caused a difference in osmotic pressure between the cerebrospinal fluid and the cyst contents, leading to rapid enlargement of the cyst. An endodermal cyst should be removed as completely as possible because its cells have the ability to grow and produce secretions.

Brainstem gliomas in adults: prognostic factors and classification

In contrast to childhood brainstem gliomas, adult brainstem gliomas are rare and poorly understood. The charts of 48 adults suffering from brainstem glioma were reviewed in order to determine prognostic factors, evaluate the effect of treatment and propose a classification of these tumours. Mean age at onset was 34 years (range 16-70 years). The main presenting symptoms were gait disturbance (61%), headache (44%), weakness of the limbs (42%) and diplopia (40%). Four patterns were identified on MRI, representing non-enhancing, diffusely infiltrative tumours (50%), contrast-enhancing localized masses (31%), isolated tectal tumours (8%) and other patterns (11%). Treatment consisted of partial resection (8%), radiotherapy (94%) and chemotherapy (56%). Overall median survival was 5.4 years. On univariate analysis, the following favourable prognostic factors were identified (P< 0.01): age of onset <40 years, duration of symptoms before diagnosis >3 months, Karnofski performance status >70, low-grade histology, absence of contrast enhancement and 'necrosis' on MRI. On multivariate analysis, the duration of symptoms, the appearance of 'necrosis' on MRI and the histological grade of the tumour remained significant and independent prognostic factors (P< 0.05). Eighty-five percent of the tumours could be classified into one of the following three groups on the basis of clinical, radiological and histological features. (i) Diffuse intrinsic low-grade gliomas (46%) usually occurred in young adults with a long clinical history before diagnosis and a diffusely enlarged brainstem on MRI that did not show contrast enhancement. These patients were improved by radiotherapy in 62% of cases and had a long survival time (median 7.3 years). Anaplastic transformation (appearance of contrast enhancement, 27%) and relentless growth without other changes (23%) were the main causes of death. (ii) Malignant gliomas (31%) occurred in elderly patients with a short clinical history. Contrast enhancement and necrosis were the rule on MRI. These tumours were highly resistant to treatment and the patients had a median survival time of 11.2 months. (iii) Focal tectal gliomas (8%) occurred in young patients and were often revealed by isolated hydrocephalus. The course was indolent and the projected median survival period exceeded 10 years. In conclusion, adult brainstem gliomas are different from the childhood forms and resemble supratentorial gliomas in adults. Low-grade tumours have a clinicoradiological pattern that is so characteristic that the need for a potentially harmful biopsy is debatable. The optimum timing of treatment for supratentorial low-grade tumours remains unclear. In high-grade gliomas, the prognosis remains extremely poor despite aggressive treatment with radiotherapy and chemotherapy.

[Tectal tumours in paediatrics. A review of eight patients]

INTRODUCTION

Tumours of the tectal region form, within the group of gliomas of the brain stem, a sub group with better prognosis which require a different therapeutic strategy.

OBJECTIVES

A retrospective review of tectal tumours in children to find the most suitable therapeutic approach and the prognosis to be expected.

PATIENTS AND METHODS

We reviewed 8 paediatric patients who, during the past 11 years, had developed tectal tumours diagnosed by means of neuro imaging techniques. We evaluated their clinical features and especially their clinico radiological progress.

RESULTS

The average age at the time of diagnosis was 10 years. All cases presented with the clinical features of raised intracranial pressure secondary to obstruction of the aqueduct of Sylvius. MR was the key to visualization of the tectal lesion in all cases but one, which had already been shown on CT. The initial and only treatment given was a ventricular shunt. The average clinico radiological follow up in our series was 4 years, with good progress in all cases so that no other therapeutic measures were required. MR follow up showed that the tumours were stable in all cases but one, which had increased slightly in size but without parallel clinical signs.

CONCLUSION

In most cases tectal tumours in children follow a benign course. A ventricular shunt is usually the only treatment necessary. However, close clinical and radiological follow up should be carried out to rule out growth of the tumour which make other treatment also necessary. MR is the method of choice for initial evaluation and follow up of these tumours.

Management of intrinsic gliomas of the tectal plate in children. A ten-year review

The natural history, management, and long-term outcome for patients with benign, intrinsic tectal plate gliomas remain controversial in spite of their propensity to cause late-onset hydrocephalus. A 10-year retrospective review has identified 11 consecutive children with tectal plate lesions. Headache, vomiting, a decline in school performance, tremor, and complex partial seizures were common presenting symptoms. All patients presented with signs and symptoms of hydrocephalus. Magnetic resonance (MR) imaging delineated an intra-axial mass lesion of the midbrain primarily localized to the tectal plate which uniformly was hyperintense on T2-weighted imaging and had a more variable appearance on T1-weighted imaging and rare enhancement with gadolinium. No patient underwent surgical resection, chemotherapy, or radiotherapy. Three of 11 patients (27%) showed evidence of progression in size or a new focus of enhancement on MR imaging, which was clinically asymptomatic. In this series, no patient with a tectal plate lesion less than 1.5 cm in maximal diameter and without gadolinium enhancement showed any evidence of clinical or radiological progression. Although intrinsic tectal lesions in children are clinically indolent and the initial management consists of CSF diversion, these lesions may eventually progress and still warrant long-term follow-up with serial MR imaging.

Globular glioma of the tectum

Brainstem gliomas are a heterogeneous group of tumors whose prognosis and treatment depend not only on the histologic features but also on the location within the brainstem. Magnetic resonance imaging allows the recognition of a distinct type of brainstem glioma of the tectal region of the midbrain, leading to aqueductal compression and hydrocephalus. The radiologic appearance of these tumors is usually rather uniform, with a characteristic nonenhancing thickening of the tectal plate. Because of its protracted course, no further treatment is necessary beyond cerebrospinal fluid diversion and close clinicoradiologic follow-up. The authors report two children with tectal plate gliomas of unusual but strikingly similar appearance. They present a clinical picture suggestive of intracranial hypertension without localizing signs. Magnetic resonance images reveal hydrocephalus related to the presence of perfectly circular lesions, hypointense on T1 and hyperintense on T2, which could be mistaken for parasitic cysts or represent dilated rostral portions of the sylvian aqueduct. After the cerebrospinal fluid diversion procedures, no further treatment was given, with one of the patients being monitored for 10 years and the other for 8 months, without tumor progression. These patients demonstrate that tectal gliomas, despite sharing a good prognosis, may have various patterns of growth, leading to unusual radiologic appearances that may pose diagnostic difficulties.

[Benign tectal tumors: clinical and neuroradiological correlations]

Benign tectal tumours in children constitute a distinct group of brainstem gliomas, characterised by a usually benign clinical course. The aim of this paper was a retrospective analysis of 1) results of conservative treatment, 2) diagnostic value of CT and MRI and 3) correlation of the MR image with the clinical course of the disease. Our material includes 15 patients aged from 6 to 16. The treatment consisted in the implantation of a CSF-shunting device (6 children), endoscopic ventriculostomy (6 children) or ventriculostomy in a child with malfunction of a previously implanted shunt (3 cases). Follow-up periods range from 3 to 219 months (mean 46.8 mo.). A slight progression of tumour in imaging studies was noted in 3 cases, while in the remaining patients neither clinical nor radiologic progression of the disease was observed. There was no correlation between tumour size and focal contrast enhancement in MRI and the natural course of the disease. The method of choice in the diagnosis of benign tectal tumours is MRI and in the treatment of associated hydrocephalus-endoscopic third ventriculostomy. An in-depth diagnostic work-up and a more aggressive cause-oriented treatment is used only in cases of a documented clinical and radiological progression.

Intracranial metastasis of Wilms' tumor involving the tectal plate without pulmonary involvement. Case report

Intracranial metastasis without pulmonary involvement of Wilms' tumor is very rare, and most previously reported metastatic sites have been in the cerebral parenchyma. We experienced a rare case of metastasis of Wilms' tumor in the tectal plate without pulmonary involvement. A 3-month-old boy was admitted to our hospital due to hydrocephalus. After insertion of a ventriculoperitoneal shunt, there were no neurological deficits. Five months after the operation, a mass 5 cm in diameter extending from the tectal plate into the third ventricle was found. A mass 10 cm in diameter within the retroperitoneal space, which occupied the right kidney, was also found. Both tumors were resected and diagnosed histologically as Wilms' tumor. Despite every effort including chemotherapy and radiotherapy, the patient died at 14 months old. The majority of children with hydrocephalus showing thickening of the tectal plate would most likely have tectal glioma; however, this unusual case report reminds us that metastasis of Wilms' tumor can occur in the tectal plate causing hydrocephalus.

Endoscopic ventriculocystocisternostomy of a quadrigeminal cistern arachnoid cyst. Case report

The authors present the case of an elderly patient with a quadrigeminal arachnoid cyst who was successfully treated with endoscopic fenestration through the posterior wall of the third ventricle via the anterior horn of the lateral ventricle. This 71-year-old man suffered from progressive gait instability and disorientation. Radiological examination revealed hydrocephalus caused by a quadrigeminal arachnoid cyst. The patient underwent endoscopic fenestration of the quadrigeminal cistern arachnoid cyst and third ventriculostomy via one burr hole placed at the coronal suture. This method is less invasive and is effective for quadrigeminal cistern arachnoid cyst and accompanying hydrocephalus.

Bilateral trochlear nerve palsy with arachnoid cyst of the quadrigeminal cistern

PURPOSE

To report bilateral trochlear nerve palsy and its magnetic resonance imaging characteristics in a patient with an arachnoid cyst of the quadrigeminal cistern.

METHOD

We performed magnetic resonance imaging of the brainstem of a 54-year-old man who had bilateral trochlear nerve palsy and mild truncal ataxia.

RESULTS

Magnetic resonance imaging disclosed an arachnoid cyst of the quadrigeminal cistern with enlargement of the lateral, third, and fourth ventricles. The tectum of the midbrain and the ambient and interpeduncular cisterns were markedly compressed by the arachnoid cyst.

CONCLUSION

These findings suggest that the bilateral trochlear nerve palsy in this patient was caused by the arachnoid cyst of the quadrigeminal cistern.

Arachnoid cyst rupture producing subdural hygroma and intracranial hypertension: case reports

OBJECTIVE

To analyze the association between arachnoid cysts and subdural hygromas.

METHODS

We reviewed five cases of arachnoid cysts that ruptured, producing acute subdural hygromas. The surgical management and diagnostic methods used are assessed.

RESULTS

Five male patients ranging in age from 6 to 25 years sustained the rupture of arachnoid cysts, which produced acute subdural hygromas. Four of the patients had incurred blunt head trauma. All patients presented with symptoms referable to intracranial hypertension. The pathognomonic features of a middle fossa arachnoid cyst (MFAC) were noted on the computed tomographic scans and/or magnetic resonance images of each patient. The hygroma exerted mass effect on the ipsilateral hemisphere and was noted to be under significant pressure at the time of surgical intervention in each case. Two of the five cases are unique in the literature. In one, a coexisting quadrigeminal cyst ruptured, producing a subdural hygroma ipsilateral to the MFAC and dilating the basal cisterns. In the other, the MFAC ruptured into the basal cisterns as well as into the subdural space. The MFAC in each of the remaining three patients ruptured into the subdural space alone. All patients were treated with drainage of the subdural space. In the two patients in whom the basal cisterns were involved, both the hygromas and the MFACs failed to change significantly in size. The hygromas resolved completely and the MFACs decreased in size considerably in the three patients without cisternal involvement.

CONCLUSION

The rupture of an arachnoid cyst can produce a subdural hygroma and intracranial hypertension. The latter mandates emergent drainage of the subdural space. In patients in whom the basal cisterns are not dilated by cyst rupture, both the MFACs and hygromas resolve after subdural drainage.

[Spontaneous hemorrhage of the quadrigeminal plate: description of two cases]

INTRODUCTION

Spontaneous mesencephalic hemorrhages are very unusual, specially those located in the tectal region. Hypertension is a less important factor that in other classical locations. Other etiologies reported are arteriovenous malformations, coagulation disorder and trauma. We describe two patients with spontaneous hemorrhage of the quadrigeminal plate.

CLINICAL CASE

Case 1: a non-hypertensive 30 year-old man who suddenly presented headache, nausea, diplopia and left hemisensory deficit. Twenty-four hours later he lost consciousness but was again alert within five hours. Examination revealed upward and downward gaze palsy and limited convergence. The patient recovered completely within six weeks. Case 2: a 38 year-old man without hypertension, who suddenly developed dizziness, occipital headache, nausea and diplopia. On examination, there was impaired upward and downward gaze, limitation of convergence and right arm hyposthesia. After eight weeks examination showed a mild limitation of upward voluntary gaze. CT and MR imaging studies revealed a small quadrigeminal hemorrhage in both cases.

CONCLUSIONS

Hemorrhages located at mesencephalic tectal region are infrequent. They have a typical clinical presentation and outcome is usually favourable. Hypertension is less common than in hemorrhages of other locations. A significant proportion of cases can be attributed to occult vascular malformations.

Magnetic resonance imaging and computed tomography characteristics of intracranial intra-arachnoid cysts in 6 dogs

Magnetic resonance imaging (MRI) and computed tomographic imaging (CT) characteristics of intracranial intra-arachnoid cysts in six dogs are described. Of the six dogs, three were less than one year of age and 4 were males. Five of the six dogs weighed less than 11 kg. Five cysts were located in the quadrigeminal cistern. On CT images, the intracranial intra-arachnoid cysts had sharply defined margins, contained fluid isodense to CSF and did not enhance following i.v. administration of contrast. On MRI images, the intracranial intra-arachnoid cysts were extra-axial, contained fluid isointense with CSF and did not enhance following i.v. contrast. While spinal arachnoid cysts of dogs have been reported in the literature, other than the six dogs contained in this report, intracranial intra-arachnoid cysts have not to our knowledge been described in animals. These six dogs have a similar age, sex, history, clinical signs, CT and MRI findings to those reported in people with intracranial intra-arachnoid cysts.

Congenital quadrigeminal lipoma with osteocartilagenous element. A case report

A case of congenital tectal lipoma found incidentally at an autopsy is reported. This female fetus was a product of pregnancy termination at 24 weeks of gestational age after sonographic detection of hydrocephalus. Autopsy revealed a small mass in the periaqueductal portion. The mass was composed of adipose tissue, cartilage, and mature bony tissue with hematopoiesis. The resultant diagnosis was tectal lipoma with osteocartilagenous element. It is uncertain whether the lesion represents a teratoma or hamartoma or mesenchymal metaplasia. The osteocartilagenous component suggests the latter.

Unusual manifestations of postnatally acquired cytomegalovirus infection: findings on CT and MR

An infant with unusual CT and MRI manifestations of postnatally acquired cytomegalovirus (CMV) infection is presented. The child exhibited extensive inflammatory lesions in the periventricular area and at the level of the quadrigeminal plate with the formation of a pseudotumour at this level. The latter produced aqueduct obstruction resulting in hydrocephalus. These findings have not previously been described in the literature.

Dorsal brain stem lipomas: case report

Intracranial lipomas are uncommon and rarely symptomatic lesions accounting for 0.06 to 0.46% of intracranial lesions. The management of symptomatic dorsal brain stem lipomas was once limited to cerebrospinal fluid diversion, but with recent advances in microsurgery, they now may be directly treated. We report three patients with dorsal brain stem lipomas, two of which involved the quadrigeminal cistern and one of which was in the cisterna magna region. Antenatal documentation by ultrasound examination in one patient represents the first reported in utero diagnosis of quadrigeminal cistern lipoma. Computed tomographic and magnetic resonance imaging scans were diagnostic. The surgical experience in two symptomatic patients is discussed. Microsurgical decompression was performed in each without neurological deficit, and clinical symptoms postoperatively subsided. No patient required a permanent cerebrospinal fluid shunt. The management of symptomatic dorsal brain stem lipomas is discussed, and an algorithm is proposed.

Burr hole neuroendoscopic fenestration of quadrigeminal cistern arachnoid cyst: technical case report

Arachnoid cysts of the quadrigeminal cistern have been managed by cyst shunting and craniotomy with cyst fenestration. Two children are presented who underwent successful burr hole neuroendoscopic fenestration of symptomatic quadrigeminal plate cysts. The literature is reviewed with regard to the treatment of quadrigeminal arachnoid cysts, and the neuroendoscopic management of these cysts is described.

Astrocytomas arising in the tectal region of the mesencephalon: report of two cases

Astrocytoma arising from the tectum of the mesencephalon is an unusual tumor that is different from other brain stem tumors in clinical features. We describe two patients with tectal low-grade astrocytoma. Each patient underwent CSF diversion and biopsy followed by radiation therapy. A review of the literature on the clinical, radiographic, and pathological findings and the management of tectal tumor is presented.

Focal tectal tumors: management and prognosis

A 7-year review at our institution identified 12 children with midbrain tectal tumors. All presented with signs of increased intracranial pressure, had hydrocephalus on initial imaging, and were treated with ventriculoperitoneal (VP) shunts. Three had clinical and radiographic progression of disease. Two were treated with radiation and chemotherapy, with progression of disease in one. The third received radiation alone. All patients are alive, with a median follow-up of over 4 years. Median progression-free survival is at least 24 months and median total survival is beyond 50 months. The tectal glioma syndrome is a relatively benign variant of the brainstem glioma. The majority of patients may be managed with a VP shunt alone.

Tectal plate gliomas. Part II: CT scans and MR imaging of tectal gliomas

CT scans and MR images were analyzed in 12 patients with histologically proved tectal plate gliomas. In an attempt to identify the nature of these lesions, their radiological characteristics were correlated with the histological results. In four of our patients CT scan failed to show the tumour. MR imaging demonstrated the tectal distortion in all cases. Contrast enhancement, calcification, cystic portions, exophytic nature were observed in both high and low-grade gliomas. We conclude that in the case of intrinsic tectal tumours, the most probable diagnosis is that of low-grade astrocytoma while in the case of exophytic tectal tumours, the differential diagnosis from pineal region tumour is required and a histological verification is necessary.

Stereotactic radiosurgery for tectal low-grade gliomas

We report 7 cases with low-grade gliomas in the tectal region of the midbrain. This series started in 1979 and all tumors were treated by radiosurgery using the Leksell Gamma Knife. All cases were treated by using a single isocenter with the 14 mm collimator. Doses administered ranged from 14 to 35 Gy delivered to the 50-70% isodose line. All tumours but one responded to the treatment and disappeared or ceased growing. In the first two treated cases, the dose was chosen by the early experience from the AVM's, with 30 and 35 Gy as the peripheral dose. These cases developed severe radio-induced oedema with aggravating symptoms and permanent deficits. We conclude that radiosurgery is effective in the treatment of deeply located low-grade gliomas. Cases accepted for treatment should be carefully selected and the peripheral dose should not exceed 14Gy to avoid uncontrolled radio-induced changes.