SPACE OCCUPYING LESIONS ( SOL).
BRAIN TUMOURS
Tumours, granulomas, abscess, cysts , aneurysms, haemangioma etc are examples of pathologies presenting as SOL in neurological cases.
SOL usually present with signs of
1.Raised ICP ( Intra cranial pressure)
& /or
2.Focal neurological deficit depending on the anatomical location of the lesion(s).
3.In addition, it may have other features depending upon type of the lesion.
PRIMARY BRAIN TUMOURS;
Primary tumours are usually slow growing with history of Weeks to months and then slowly progressive worsening of focal neurological deficits is typical. GBM is a rapidly growing tumour and can have necrosis/ bleeding etc whereas other primary brain tumours are slow growing and usually don’t have bleeding or necrosis.
Tumour Calcification is commonly seen in meningiomas and Astrocytomas. These can be in layers and called Psammoma bodies. This is dystrophic calcification.
Pituitary tumours will also give hormonal abnormalities whereas hypothalamic can affect hormones or basic needs of like sleep, hunger, sex or temperature regulation etc. Pineal gland is close to cerebral aqueduct in mid brain, hence causing hydrocephalus and affecting vertical gaze etc. Similarly other tumours will also give focal signs depending on their location.
Metastasis out of brain is extremely rare and hence systemic mets are almost always not seen in Primary brain tumours. However spread within the CNS can happen due to CSF invasion. GBM (being rapidly growing ) and Ependymoma (being within CSF ) are more likely to spread through CSF. Medulloblastoma (being very close to 4th ventricle in Cerebellar vermis is also easy to spread. As there are usually not metastatic tumours, cachexia etc are usually not commonly seen unlike metastatic ( secondary)brain tumours with primary elsewhere.
Posterior fossa ( Infra tentorial )tumours are more common in paediatrics and supra tentorial are more common in adults.
All the brain tumours are more common in males except Meningiomas and Schwanomma which are more in females. Both of these are outside the actual brain tissue, one in meninges and other around the nerves and hence can also erode the adjacent bones, a feature not seen in other primary brain tumours. Also both of these are surgical accessible and resection is easy.
Location: Usually the name of the tumour will give a clue about its location. Eg Medulloblastoma, Pinealoma, Pituitary Adenoma , Cerebellar Astrocytomas , Ependymoma etc. If the name is not helpful then most most likely it’s frontal lobe in adults & posterior fossa in children. Eg Glioblastoma Multiforme is most commonly seen in frontal lobe.
Types:Brain tissues has neurons, glial cells, astrocytes, Ependymal cell lining ventricles, pituitary and pineal glands, meninges covering the brain etc, so tumours are named after its cells of origin.
Immunocompromised patients are more likely to have Primary Brain Lymphomas as well, which are extremely uncommon in otherwise immunocompetent persons.
Treatment mainly depends on surgical resectability which is determined by many factors including location of the tumour. Targeted Radiotherapy is another alternate option. Chemotherapy may also be used.
METASTATIC BRAIN TUMOURS;
Many tumours have mets to brain & it’s not always possible to pinpoint the primary tumours.
Necrosis is usually less likely in metastatic tumour as Mets mostly settle in vascular areas. Similarly calcification is also less likely in mets. Mets are usually multiple although single lesions are also often seen. Grey white junction is usually a preferred site within brain.
Underlying primary tumour and its related clues may be useful if present. Mostly patients with metastatic disease are quiet cachectic unlike primary brain tumours.
Tissue diagnosis isn’t an easy job if primary tumour isn’t evident. Mostly these patients are sick enough & are often palliated.