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VI./4.2.: Presentation
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Presentation of brain metastasis does not differ significantly from primary brain tumors or other slowly growing space-occupying lesions. Multiple metastatic lesions are indicated by symptoms suggesting simultaneous damage of multiple areas of the brain. The location of the metastases in the brain are the hemispheres (85%), the cerebellum (10%) and the brain stem (5%).
Non-specific but characteristic complaints may suggest metastatic disease, like behavioural disturbance, changes of personality and progressive headache (worse in the morning, increased frequency and intensity or change in character). In most cases, focal symptoms or focal epileptic seizure depending on the location of the lesion are the first symptomes leading to diagnosis. Metastatic brain tumors have to be excluded in every older patients with new onset focal or secondarily generalized seizures.
Brain metastases usually cause subacute onset because of their slow growth, with symptoms progressing over weeks to months. Sudden worsening of the focal symptoms may occur in the case of tumor haemorrhage. This clinical course is typical of rapidly growing or highly vascularised tumors such as malignant melanoma, hypernephroma, thyroid gland carcinoma or choriocarcinoma. Peritumoral arterial compression could cause similar progression, may mimic ischemic lesion.
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Eloquent areas, the speech center, primary motor cortex of the brain have to be mentioned since their dysfunction (e.g. aphasia, paresis) will probably lead to earlier investigation and diagnosis. Subdominant parieto-occipital or prefrontal cortical metastases could first appear as psycho-organic syndrome with behavioural symptoms, cortical dysfunction or poor initiative suggesting mental illness, depression delaying investigations for a long period until other alarming symptoms (such as seizures or increased intracranial pressure) appear.
Brain metastases trigger large vasogenic, so called perifocal oedema. Part of the symptoms are caused by the dysfunction of the swelled brain tissue which size could be multiple of the tumor itself. Symptoms may be reversible by decreasing the extent of brain swelling.
Tumor infiltration of the meninges (leptomeningeal carcinomatosis) is accompanied with headache and specifically with multiple peripherial cranial nerve dysfunction (double vision, facial nerve palsy, trigeminal neuralgiform pain) caused by the compression or infiltration of the cranial nerves or basal cisterns. In the spinal column the similar phenomenon will lead to spinal radicular lesions. Only haematologic tumors, e.g. lymphomas, acute lymphoid leukemias result in leptomeningeal manifestation alone (without solid metastasis). Malignant melanomas, bronchial and breast carcinomas may present as leptomeningeal only or simultaneous (meningeal and solid) metastases .
Universal symptoms caused by increased intracranial pressure and herniations are important to mention. Along with the focal symptoms, patients will present with signs of general cortical dysfunction and progressive disturbance of consciousness. The effect of multiple metastases and large perifocal oedema are added together as cause of increased intracranial pressure. A small tumor blocking the cerebrospinal fluid circulation will lead to occlusive hydrocephalus with the same result.
Paraneoplastic syndromes are general or multiple neurological symptoms caused by tumors not directly infiltrating the nervous system. The most common paraneoplastic syndromes are limbic encephalitis in patients with pulmonary carcinomas and cerebellar degeneration usually found in patients with small cell lung or ovarian cancer.
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Patients with brain metastasis at the same time of having systemic cancer (synchronous metastasis have the worst prognosis. General condition, oncologic stage, accompanying diseases have prognostic value which could modify the treatment strategy. Certain cerebral metastases, such as malignant melanoma are tend to re-grow, even with aggressive multimodal oncologic treatment.
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