Table 27.6 Open in new tab Imaging...

Table 27.6

Imaging characteristics and pointers towards diagnosis of common intrinsic tumours of the brain

	Pilocytic astrocytoma	Astrocytoma	Oligodendroglioma	Medulloblastoma	Malignant glioma	Metastasis	Primary CNS lymphoma	Germ cell tumour
Peak age	10–30 yr	20–40 yr	20–50 yr	1–20 yr	40–70 yr	50–80 yr	50–70 yr	10–30 yr
Site	Usually cerebral or midline cerebellar	Adult cerebral; child cerebellar	Frontotemporal	Cerebellum, IV ventricle	Cerebral	Anywhere	Periventricular, anywhere	Pineal, suprasellar
Single/multiple	Single	Single	Single	Single/CSF	95% single	33% single	60% single CSF>20% Vitreous>20%	90% single CSF>20%
Usual characteristics
Borders	Well demarcated	Diffuse/infiltrating	Well defined	Well defined	Serpiginous	Well defined	Indistinct	Distinct
Cysts	Common	Uncommon	Uncommon	Uncommon	Occ. necrotic	Occasionally	Nil	Occasionally
Calcification	10–40%	5–10%	50%	Nil	<5%	<3%	Nil	10–15%
Peritumoral oedema	Nil or mild	Mild	Mild	Moderate	Moderate	Moderate/severe	Mild/severe	Nil/mild
Mass effect	Nil or mild	Mild	Mild/moderate	Moderate	Moderate	Moderate/severe	Mild/severe	Nil/mild
Investigations
CT	Low density	Low density	Low density	Occ. high density	Low density	Low density	Occ. high density	Low density
	Enhancing nodule	No enhancement	No enhancement	Enhancement	Border enhances	Uniform/border	Uniform/border	Uniform
T₁-MRI	Iso/hyperintense	Hypointense	Hypointense	Hypointense	Hypointense	Hypointense	Hyper/isointense	Iso/hypointense
T₁ Gad-MRI	Enhancing nodule	No enhancement	No enhancement	Enhancement	Border enhances	Uniform/border	Uniform/border	Uniform
T₂-MRI	Hyperintense	Hyperintense	Hyperintense	Hyperintense	Hyperintense	Hyperintense	Hyperintense	Hyperintense
Other helpful tests	–	–	–	MRI spine	–	Chest/abdo. CT	Slit-lamp (eyes)	CSF
				CSF		Tumour markers	CSF	Tumour markers
Differential diagnosis	Abscess	Multiple sclerosis	Meningioma	Astrocytoma	Abscess	Stroke	Multiple sclerosis	Meningioma
	Malig. glioma	Infarct	AVM	Malig. glioma	Stroke	Abscess	Sarcoid	PNET
	Ganglioglioma	Oligodendroglioma	Astrocytoma	Lymphoma	Metastasis	Malig. glioma	Metastasis	Malig. glioma
	Craniopharyngioma	Malig. glioma	Craniopharyngioma	Germinoma	Oligodendroglioma	Lymphoma	Malig. glioma	Metastasis
	Germinoma		Malig. glioma		Lymphoma		Toxoplasmosis

	Pilocytic astrocytoma	Astrocytoma	Oligodendroglioma	Medulloblastoma	Malignant glioma	Metastasis	Primary CNS lymphoma	Germ cell tumour
Peak age	10–30 yr	20–40 yr	20–50 yr	1–20 yr	40–70 yr	50–80 yr	50–70 yr	10–30 yr
Site	Usually cerebral or midline cerebellar	Adult cerebral; child cerebellar	Frontotemporal	Cerebellum, IV ventricle	Cerebral	Anywhere	Periventricular, anywhere	Pineal, suprasellar
Single/multiple	Single	Single	Single	Single/CSF	95% single	33% single	60% single CSF>20% Vitreous>20%	90% single CSF>20%
Usual characteristics
Borders	Well demarcated	Diffuse/infiltrating	Well defined	Well defined	Serpiginous	Well defined	Indistinct	Distinct
Cysts	Common	Uncommon	Uncommon	Uncommon	Occ. necrotic	Occasionally	Nil	Occasionally
Calcification	10–40%	5–10%	50%	Nil	<5%	<3%	Nil	10–15%
Peritumoral oedema	Nil or mild	Mild	Mild	Moderate	Moderate	Moderate/severe	Mild/severe	Nil/mild
Mass effect	Nil or mild	Mild	Mild/moderate	Moderate	Moderate	Moderate/severe	Mild/severe	Nil/mild
Investigations
CT	Low density	Low density	Low density	Occ. high density	Low density	Low density	Occ. high density	Low density
	Enhancing nodule	No enhancement	No enhancement	Enhancement	Border enhances	Uniform/border	Uniform/border	Uniform
T₁-MRI	Iso/hyperintense	Hypointense	Hypointense	Hypointense	Hypointense	Hypointense	Hyper/isointense	Iso/hypointense
T₁ Gad-MRI	Enhancing nodule	No enhancement	No enhancement	Enhancement	Border enhances	Uniform/border	Uniform/border	Uniform
T₂-MRI	Hyperintense	Hyperintense	Hyperintense	Hyperintense	Hyperintense	Hyperintense	Hyperintense	Hyperintense
Other helpful tests	–	–	–	MRI spine	–	Chest/abdo. CT	Slit-lamp (eyes)	CSF
				CSF		Tumour markers	CSF	Tumour markers
Differential diagnosis	Abscess	Multiple sclerosis	Meningioma	Astrocytoma	Abscess	Stroke	Multiple sclerosis	Meningioma
	Malig. glioma	Infarct	AVM	Malig. glioma	Stroke	Abscess	Sarcoid	PNET
	Ganglioglioma	Oligodendroglioma	Astrocytoma	Lymphoma	Metastasis	Malig. glioma	Metastasis	Malig. glioma
	Craniopharyngioma	Malig. glioma	Craniopharyngioma	Germinoma	Oligodendroglioma	Lymphoma	Malig. glioma	Metastasis
	Germinoma		Malig. glioma		Lymphoma		Toxoplasmosis

abdo., Abdominal; AVM, arterio-venous malformation; CNS, central nervous system; CSF, cerebrospinal fluid; Gad, gadolinium; Malig., malignant; Occ., occasional(ly); PNET, primitive neuro-ectodermal tumour.

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