Multiple intracranial lesions

Multiple Intracranial Parenchymal Lesions Evolving Over a Decade ¹⁾.

1. neoplastic

a) primary

● multicentric gliomas; ≈ 6% of gliomas are multicentric, more common in neurofibromatosis, see Multiple gliomas

● tuberous sclerosis (including giant cell astrocytomas); (usually periventricular)

● multiple meningiomas

● lymphoma: see Multiple Primary central nervous system lymphoma.

● PNET

● multiple neuromas (usually in neurofibromatosis, including bilateral vestibular schwannomas)

b) metastatic: usually cortical or subcortical, surrounded by prominent vasogenic edema

More common tumors include:

● lung cancer

● breast cancer

● melanoma: may be higher density than brain on unenhanced CT

● renal cell

● gastrointestinal tumors: Gastrointestinal tract brain metastases.

● genitourinary tract tumors

● choriocarcinoma

● testicular

● atrial myxoma

● leukemia

2. infection: mostly abscess or cerebritis. Most commonly due to:

a) pyogenic bacteria

b) toxoplasmosis: common in AIDS patients

c) fungal

● cryptococcus

● mycoplasma

● Coccidioidomycosis

● aspergillosis

● candidiasis

d) echinococcus

e) schistosomiasis

f) paragonimiasis

g) herpes simplex encephalitis (HSE): usually temporal lobe

3. inflammatory

a) demyelinating disease

● MS: usually in white matter, periventricular, with little mass effect, margins are usually very sharp. Ring enhancing lesions can occur with tumefactive demyelinating lesions

● progressive multifocal leukoencephalopathy (PML): primarily in white matter. No enhancement. Patients are usually very sick

b) gummas

c) granulomas

d) amyloidosis

e) sarcoidosis

f) vasculitis or arteritis

g) collagen vascular disease, including:

● periarteritis nodosa (PAN)

● systemic lupus erythematosus (SLE)

● granulomatous arteritis

4. vascular

a) multiple aneurysms (congenital or atherosclerotic)

b) multiple hemorrhages, e.g. associated with DIC or other coagulopathies (including anticoagulant therapy)

c) venous infarctions, especially in dural sinus thrombosis

d) moyamoya disease

e) subacute hypertension (as in malignant HTN, eclampsia…) → symmetric confluent lesions with mild mass effect and patchy enhancement, usually in occipital subcortical white matter

f) multiple strokes

● lacunar strokes (l’etat lacunaire)

● multiple emboli (e.g. in atrial fibrillation, mitral valve prolapse, SBE, air emboli)

● sickle cell disease

● vasculitis

● intravascular lymphomatosis

5. hematomas and contusions

a) traumatic (multiple hemorrhagic contusions, multiple SDH)

b) multiple “hypertensive” hemorrhages (amyloid angiopathy, etc.)

6. intracranial calcifications: Multiple intracranial calcifications.

7. miscellaneous

a) radiation necrosis

b) foreign bodies (e.g. post gunshot wound)

c) periventricular low densities

● Binswanger’s disease

● Transependymal edema (e.g. in active hydrocephalus)

Deciding which of the following tests are needed to evaluate a patient with multiple intracranial lesions must be individualized for the appropriate clinical setting.

1. cardiac echo: to R/O SBE that could shed septic emboli

2. “Intracranial metastases workup” including:

a) CT of chest/abdomen/pelvis with and without contrast: has become a relatively standard part of the metastatic workup. It has largely supplanted CXR, lower GI (barium enema) and IVP.

Rationale:

● Chest: R/O primary bronchogenic Ca or pulmonary metastases of another Ca. Can demonstrate mediastinal lymphadenopathy. Also to R/O pulmonary abscess that could shed septic emboli

● Assesses for possible primary lesions: e.g. kidneys, GI, prostate

● Evaluates for metastases to liver, adrenal, and even spine

b) mammogram in women

c) PSA in men