Computed tomography scan of the brain of a patient with a meningioma

Computed tomography scan of the brain of a patient with a meningioma

Case history

An 89 year old woman was admitted as an emergency after a fall at home. She was unable to recall the events leading up to the fall and was unable to say whether she had lost consciousness. Her home help had not witnessed the fall but accompanied her to the hospital. The help noted that the patient seemed very confused after the fall but felt that four hours later she was back to her normal self. Over the past two years the patient had had several falls and had been admitted to hospital three months earlier, also after a fall, in which she had sustained a soft tissue injury.

Her past medical history included hypothyroidism, angina, pernicious anaemia, and a basal cell carcinoma on her left cheek. Current medications included aspirin, thyroxine, isosorbide mononitrate, and neocytamen injections.

She lived alone in sheltered accommodation and received daily home help. She was teetotal and a lifelong non-smoker.

Physical examination was unremarkable with the exception of a recurrent basal cell carcinoma on her left cheek and absent ankle jerks but no other focal deficit. There was no evidence of postural orthostatic hypotension or any abnormality on neck examination (Hallpike manoeuvre). Results of a full blood count, a chemical profile, random blood glucose testing, and dipstix of urine were unremarkable. Her 12 lead electrocardiogram showed sinus rhythm normal axis and chest x ray clear lung fields. Some 24 hours into her admission she had a tonic-clonic seizure witnessed by the nursing staff looking after her and a computed tomography scan of her brain was arranged (figure 1). She declined to consider further treatment but agreed to taking an anticonvulsant and dexamethasone.

Computed tomography scan of the brain of a patient with a meningioma Questions

1. What does the CT scan show?
2. What is the diagnosis?
3. Name two symptoms that patients with this condition might complain of.

Answers

1. The scan shows a lesion within the occipital/parietal lobe on the left adjacent to the posterior inner table and falx. The lesion shows marked enhancement with white matter oedema.
2. Intracerebral tumour most likely to be a meningioma.
3. Patients with raised intracranial pressure may complain of:

• diffuse headache, worse in the morning when lying flat and aggravated by manoeuvres that cause a further rise in intracranial pressure, such as coughing and bending.
• clouding of consciousness, behavioural and personality changes.
• dizziness, true rotatory vertigo, or sensations of unsteadiness often aggravated by head movements.

Discussion

Meningiomas make up about one fifth of intracranial tumours. Meningiomas arise from the arachnoid cell clusters associated with the arachnoid villi or points of entry and exit of blood vessels and the cranial nerves through the dura. These tumours are discrete and vary in size from a small pea to that of an orange. They are rarely multiple unless associated with von-Recklinghausen syndrome. Most cause symptoms by compression. Patients may have a long history of seizures with progressive neurological symptoms and evidence of raised intracranial pressure. Meningiomas may invade the skull to cause hyperostosis but very rarely invade the pia or cortex.

Meningiomas are usually round or nodular and well circumscribed, compressing and displacing adjacent parts of the nervous system. They are almost always benign, encapsulated, attached to the dura mater. In adults, most occur in the parasagittal falx region followed by the convexity of the cerebral hemispheres and the sphenoid ridge.

Symptoms and signs are similar to those of other intracranial tumours, but their predilection for certain sites and the tendency for hyperostosis of the skull present special features that facilitate diagnosis.

Computed tomography is 95% accurate in identifying the presence of meningiomas. They present as homogeneous, highly contrast enhanced tumours with well defined borders and striking cerebral oedema in adjacent brain tissue.

Meningiomas grow slowly but eventually may grow sufficiently large to cause death by compression of cerebral tissue. Although benign, complicating factors such as location, involvement of adjacent structures, and extreme vascularity result in an operative mortality of 5-10%. Surgical treatment of meningiomas is more uniformly successful than surgical treatment of any other brain tumour.

Rosemary Morgan, consultant, Department of Medicine for the Elderly, Arrowe Park Hospital, Upton, Wirral, Merseyside CH49 5PE


studentBMJ 2003;11:131-174 May ISSN 0966-6494