Intracranial tumors (summary)

This is a basic article for medical students and other non-radiologists

Intracranial tumors comprise a heterogeneous group of tumors. In adult patients, the majority represent metastatic disease with a smaller proportion being primary brain tumors. Metastasis to the brain occurs, most commonly, from lung, breast, melanoma, renal cell, and colorectal cancers.

Reference article

This is a summary article; read more in our article on intracranial tumors.

Summary

• epidemiology
  • incidence increases with age
  • equivocal gender distribution
  • risk factors
    • malignancy elsewhere
• presentation
  • headache
  • features of raised intracranial pressure
    • nausea & vomiting worse in the morning or positional
  • altered mental state
  • focal neurology may occur as the tumor grows
  • adult-onset seizures
  • incidental finding
    • some tumors may not cause symptoms
    • patients may be imaged for another reason, e.g. trauma
• pathophysiology
  • heterogeneous group of tumors
    • metastases, e.g. lung, breast, renal
    • meningiomas
    • primary parenchymal tumors
    • pituitary or pineal tumors
    • cranial nerve schwannomas
  • tumors are graded using the WHO grade
• investigation
  • CT is often the first test performed to assess presenting symptoms
  • MRI may be used with symptoms of headaches or seizures
  • MRI is the investigation of choice to characterize the tumor
• treatment
  • parenchymal brain tumors generally have a poor prognosis
  • treatment should be in specialist centers
    • steroids may alleviate symptoms caused by edema
    • anti-epileptic agents may help for those with seizures
    • a biopsy may be performed neurosurgically
    • some tumors may be removed, e.g. pituitary tumors
    • stereotactic radiotherapy can be used for small lesions

Imaging

• role of imaging
  • confirm intracranial abnormality and prioritise MRI
  • tumor characterization
  • help to determine the grade, and make a decision about biopsy
  • follow up
• radiographic features
  • CT
    • often the first line test
    • variety of appearances depending on the tumor
    • hypo- or hyperdense, irregular, well-defined, peripheral or deep
    • useful to determine edema and mass effect
    • contrast may make lesions more conspicuous
    • CT is especially helpful for determining bony involvement
  • MRI
    • investigation of choice
    • fantastic contrast and spatial resolution
    • origin of tumors can be determined
    • different sequences are used to determine the likely diagnosis
    • specialized sequences can be useful to look at tumor metabolites