Relative value of magnetic resonance spectroscopy, magnetic resonance perfusion, and 2-(18F) fluoro-2-deoxy-D-glucose positron emission tomography for detection of recurrence or grade increase in gliomas

In a consecutive series of 26 previously operated patients diagnosed with cerebral glioma, magnetic resonance spectroscopy (MRS), 2-((18)F) fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET), and perfusion MRI (MRP), were performed at follow-up to distinguish recurrence from radiation necrosis, and to identify tumour upgrading. Discrepancy between techniques was observed in 9 cases. The positive predictive value (PPV) and the negative predictive value (NPV) of each technique to detect the presence of high grade glioma was: MRI, PPV=50%; MRS, PPV=91.6%, NPV=100%; FDG-PET, PPV=75%, NPV=61.1%; MRP, PPV=100%, NPV=100%. In the selected group of nine cases studied to differentiate viable tumour from radiation necrosis, MRS and MRP reached a PPV and a NPV of 100%, whereas for FDG-PET, PPV and NPV were 66.6% and 60%, respectively. To distinguish between viable high-grade glioma and radiation necrosis, gadolinium-enhanced MRI gives a high false-positive rate, while MRS and MRP are superior to FDG-PET in discriminating tumour recurrence, grade increase and radiation necrosis.

[Endoscopy-assisted surgery of the sellar region]

OBJECTIVE

To evaluate the usefulness of endoscopic assisted surgery of pituitary adenomas in transesphenoidal surgery, and in surgery of craneopharyngiomas using either minimally invasive approaches to the cranial base or transventricular approaches.

MATERIAL AND METHODS

We present our preliminary experience in eleven patients operated of sellar region tumor by endoscopic assisted resection: 6 pituitary adenoma via transesphenoidal approach, 4 craneopharyngiomas 3 through supraciliar approach and 1 by transcortical transventricular approach, and 1 suprasellar cyst.

RESULTS

By using the 30 degrees optic the use of endoscope allowed complete resection, confirmed by postoperative MRI, of all six pituitary macroadenomas providing control of resection of supraselar remnants. Complete resection was achieved in three out of four craneopharyngiomas, 2 of them being recurrences. Three were operated by using a supraciliar approach to the cranial base and in one case transcortical transventricular resection of a recurrent intraventricular craneopharyngioma was performed. In the case with partial resection remnant were let in place due to the close adherence to peritumoral structures. In the three craneopharyngiomas operated via supraciliar approach endoscope allowed better control of inferior aspect of ipsilateral optic nerve and internal carotid artery. In the case of intraventricular craneopharyngioma, the use of 30 degrees endoscope provide control of resection of the anterior part of third ventricle through the foramen of Monro with no additional opening. The suprasellar cyst was fenestrated.

CONCLUSIONS

No matter which approach is going to be used in the resection of sellar tumors, endoscopy can play a crucial role in achieve complete resection with minimal morbidity by using minimally invasive procedures.

Giant occipital intradiploic epidermoid cyst associated with iatrogenic puncture

The origin of cranial epidermoid cysts (EC) remains controversial, and although generally considered to be congenital, acquired origin has been reported. EC represent 0.2 to 1.8% of all brain tumours, and only one fourth are intradiploic in location. We report of a 44-year-old woman with a giant intradiploic EC of the occipital bone with intracranial extension confirmed on brain MRI. Three years previously, in the same location, she underwent resection of an intradermal melanocytic naevus of the skin under local anaesthesia with lidocaine infiltration of skin and periosteum. Brain CT scan performed at the time of naevus surgery because of associated headache did not show a lesion of the cranial vault. Iatrogenic epidermoid tumours are extremely rare, and although seeding of epidermal cells has been classically described only after lumbar puncture, the same mechanism may be involved after head injury, cranial surgery or cranial periosteal iatrogenic puncture.

[Association between cerebral infarction and malignant glioma]

INTRODUCTION

It is very rare for cerebral infarction to be the first symptom of an intracranial tumour. Only three cases have been reported in which cerebral infarction is thought to have been caused by the arterial compromise triggered by incipient high grade gliomas that are not yet visible in radiological tests.

CASE REPORT

A 46-year-old male with no relevant medical history or cardiovascular risk factors who presented with acute hemiplegia on the right-hand side of the body and a significantly impaired level of consciousness. Computerised axial tomography of the brain showed a left frontal malignant ischemic infarct that exerted an important mass effect. The patient was submitted to a left-side frontoparietal decompressive craniectomy. Post-operative progress was good and the patient even recovered his normal level of consciousness, although he was left with right hemiparesis and conduction dysphasia. Seven months after the craniectomy the patient experienced a progressive deterioration with symptoms of endocranial hypertension. Magnetic resonance imaging of the brain revealed the presence of a highly malignant tumour in the previously infarcted territory. A histological study of the excised lesion showed it to be a glioblastoma multiforme.

CONCLUSIONS

The proximity in time, as well as the identical location of the two lesions, led us to think that the glioblastoma, although not yet visible in radiological explorations, affected a branch of the middle cerebral artery and gave rise to the infarct. Therefore, in the presence of a cerebral infarct in patients with no risk factors for suffering a brain vascular pathology, it is advisable to carry out a radiological follow-up so as to be able to diagnose a possible lesion due to a tumour.

[Multiseptated arachnoid cyst treated with fenestration after valvular insufficiency in an adult. ]

Treatment of symptomatic arachnoid cysts is based on two procedures: cyst fenestration versus derivation of CSF. Multiseptated cysts represent a very special group. We present the case of a 75 year old woman with a symptomatic multiseptated arachnoid cyst, developing subacute bleeding in one of the cavities. Final diagnosis was obtained after MRI. CSF derivation became insufficient with clear improvement after fenestration and communication to subarachnoid space.

[Cauda syndrome due to spinal stenosis and diskytis in two different spinal levels. Diagnosis using myelo-TC]

We report a case of a 75 year old man presenting with paraparesis, urinary incontinence and saddle anesthesia evolving after several months and severe lumbalgia and bad general status which developed fewdays before admission. CT-scan showed spondilosis with lytic lesion at L5-S1 level. MR1 was not performed because the patient had a pacemaker. A myelo-CT study was performed showing a complete stop at L4-L5 level together with L5-S1 diskytis. Laminectomy of L5 and discectomy L5-S1 was performed obtaining tissue sample diagnostic of diskytis and osteomyelitis. Our patient had two lesions at two different levels with two independent syndromic appearence. Myelo-CT played an important diagnostic role in this case because MRI study could not be obtained.

[Posterior fossa venous epidural hematoma. Based on 2 cases]

We present two rare cases of posterior fossa epidural hematoma (PFEH) due to occipital fracture and tearing of transverse sinus. One of the patients showed supratentorial and infratentorial extension, which is found in half of the PFEH cases. Both cases experienced clinical worsening within 48 h of the head injury, with control CT showing increase of haematoma volume. Both patients were elected for surgery consisting of suboccipital craniectomy, control of sinus bleeding and sealing of epidural space with dural fixation. Sources of bleeding of PFEH are, by order of frequency, transverse sinus, small dural arteries and sigmoid sinus. PFEH may cause fatal clinical outcome with less volume than supratentorial ones. PFEH have high mortality if not treated. Patients with PFEH and GCS <15 should be admitted to hospital and a control CT should be done if there is deterioration or in the first 24 hours. The treatment of choice is surgery, conservative therapy being an alternative for small PFEH and good clinical evolution.

[Cerebral neuroblastomas: diagnosis and treatment]

AIMS

To review the literature on cerebral neuroblastomas (CN), including their anatomopathological filiation, clinical characteristics together with those they display in imaging studies, and the different therapeutic options with their prognosis.

METHOD

Cerebral neuroblastomas belong to the group of primitive neuroectodermal tumours (PNET), also known as cerebral meduloblastomas or supratentorial PNET. They originate in the supratentorial compartment and histologically they are in the WHO grade IV. They display unspecific clinical features and in imaging studies they behave like solid masses with a cystic or necrotic component, often with calcifications. Microscopically they are made up of undifferentiated or poorly differentiated neuroepithelial cells. CN express synaptophysin and other neuroendocrine markers, which can only be studied by performing neuronal differentiation analyses. First choice treatment is surgery performed as radically as possible associated with chemotherapy or whole brain radiotherapy. Results vary greatly according to age and the degree to which the lesion has spread. Worse prognoses have been described for children under 2 years old than for those above that age. Survival rate at 3 years of age, including paediatric patients, is 60%.

CONCLUSIONS

CN are not very frequent tumours, whose clinical characteristics and those displayed by imaging techniques are unspecific. Treatment must involve radical excision associated with chemotherapy or radiotherapy.