Spinal extradural arachnoid cysts: clinical, radiological, and surgical features

Extradural arachnoid cysts in the spine are rare and are seldom a cause of spinal cord compression. They are thought to arise from congenital defects in the dura mater, and they almost always communicate with the intrathecal subarachnoid space through a small defect in the dura. The mainstay of treatment in patients with neurological symptoms is surgical removal of the cyst together with ligation of the communicating pedicle and closure of the dural defect. In the present paper the authors review the literature and discuss the clinical and pathological features, mechanisms of pathogenesis, neuroimaging characteristics, and surgical management of spinal extradural arachnoid cysts. The surgical technique for removal of these lesions is illustrated in a patient with a large thoracolumbar spinal extradural arachnoid cyst causing neurogenic claudication.

Management of leptomeningeal malignancy

Leptomeningeal carcinomatosis is defined as malignant infiltration of the pia matter and arachnoid membrane. Leukaemias and lymphomas, lung, breast cancer and melanoma are the primary tumours commonly associated with leptomeningeal carcinomatosis. Diagnosis is based on compatible symptoms and signs, cytological evidence of malignancy in the cerebrospinal fluid, and neuroimaging studies. Treatment is largely palliative (median survival 2-4 months). Patients with lympomatous or leukaemic meningitis, chemosensitive tumours such as breast cancer, low tumour burden, minimal neurological deficits, good performance status and controllable systemic disease survive longer with occasional long-term responses. Available treatment options include focal radiation therapy to CNS sites of bulky, symptomatic or obstructive meningeal deposits, intrathecal cytotoxic therapy and systemic chemotherapy. No evidence of superiority of intrathecal treatment compared with best palliative care (including radiation therapy and systemic treatment) is available from clinical trials. Novel treatment approaches include intrathecal liposomal Ara-C, the development of new cytotoxic compounds, signal transduction inhibitors and monoclonal antibodies for intrathecal or systemic use. Until data from multi-centre randomised trials are available, rationalisation of therapy should be done by stratifying patients to prognostic groups. High-risk patients will only survive for a few weeks and are better managed with supportive measures, whereas low-risk patients justify vigorous cerebrospinal fluid-directed treatment combined with radiation therapy and systemic chemotherapy.

Primum non nocere: Multimodality management strategies when multiple mass lesions strike a single patient

BACKGROUND

The management of multiple symptomatic intracranial pathological processes in a single patient presents a rare and challenging problem for the neurosurgeon and the patient. Neurosurgeons must utilize a full spectrum of neurosurgical options to achieve the best patient outcome.

CASE DESCRIPTION

We present a unique case of a 63-year-old woman who presented with a large convexity meningioma causing headaches, an acoustic neuroma causing deafness and imbalance and a suprasellar arachnoid cyst compromising the visual fields. Therapeutic intervention was staged based on the primum non nocere concept. First, the patient underwent stereotactic intracavitary cyst irradiation using colloidal 32P. Secondly, microsurgical resection of the convexity meningioma was performed. Finally, Gamma Knife radiosurgery of the acoustic neuroma was performed. One year after multimodality management, the patient was neurologically improved. There was no evidence of meningioma or cyst recurrence and the growth of the acoustic neuroma was arrested.

CONCLUSION

This case demonstrates the value of multi-modality treatment of neurosurgical pathology, utilizing minimally invasive techniques when possible.

Successful management of sellar and suprasellar arachnoid cysts with stereotactic intracavitary irradiation: an expanded report of four cases

OBJECTIVE

Sellar and suprasellar arachnoid cysts may be asymptomatic or may cause headache, optic nerve compression, endocrine dysfunction, or hydrocephalus. We propose a minimally invasive treatment strategy when intervention is indicated.

METHODS

Four patients with sellar and suprasellar arachnoid cysts presented with headache, visual compromise, and endocrine dysfunction. Two of the four patients previously had undergone unsuccessful surgical intervention. The imaging studies of two patients were diagnostic of an arachnoid cyst.

RESULTS

All four patients underwent stereotactic intracavitary radiation with cyst regression and symptomatic improvement. In each patient, the optic chiasm was decompressed successfully. There were no complications from the procedure.

CONCLUSION

Stereotactic intracavitary irradiation of arachnoid cysts proved to be safe and effective. The procedure obviated the need for open cyst fenestration or shunting.

[Intracranial arachnoidal cysts--localization, gender and sidedness]

The aim of the present study was to investigate whether data on location and distribution of intracranial cysts in a large patient population may explain why and how such cysts are formed. We investigated 123 patients with 129 intracranial cysts, consecutively admitted to the Department of Neurosurgery in Bergen 1988-97. Data were analyzed with regard to intracranial location and gender distribution. Cysts were much more commonly located in the temporal fossae than one would expect if the distribution were random; 68.1% of patients had temporal cysts. We suggest a theory that may explain how mal-development of the leptomeninges may contribute to the formation of cysts, and why such cysts are more common in the temporal fossae. Temporal cysts were significantly more frequent in males than in females (3.9:1), while cysts of other locations did not show preponderance for a specific gender. New in this study is the interesting connection between gender distribution and sidedness: the significant predominance of left-sided temporal cysts was found only in males. In patients with a unilateral temporal cyst, the left/right ratio was 2.0:1 (males 44 left and 20 right, females eight left and six right). We discuss whether the preponderance of left-sided temporal cysts in males can be explained by a gender specific developmental failure, as previously suggested for dyslexia.

Intracavitary irradiation with colloidal phosphorus-32 for treatment of an arachnoid cyst: a new approach

Intracavitary irradiation is reported as an additional treatment for intracranial arachnoid cysts that do not communicate with the subarachnoid space. A 46-year-old woman with a large suprasellar arachnoid cyst that had enlarged over a 4-year interval presented with new onset headaches. Stereotactic intracavitary irradiation was performed using colloidal phosphorus-32 as an alternative to craniotomy or insertion of a shunt. Total regression of the cyst occurred within one month with resolution of her headaches. After three years of follow-up, imaging studies showed only an empty sella appearance, and no cyst recurrence. No early or delayed morbidity occurred. Intracavitary irradiation may be a useful therapy for arachnoid cysts, in an attempt to alter the biology of the cyst lining.