Tuberculoma - ICUNOTES

Tuberculoma (CNS Tuberculoma)

A tuberculoma is a localized granulomatous mass lesion caused by infection with Tuberculosis in the central nervous system (CNS). It represents a focal immune response to Mycobacterium tuberculosis and appears as an intracranial or spinal space-occupying lesion.

Unlike tuberculous meningitis (TBM), tuberculoma is predominantly a parenchymal disease and may occur with or without meningitis.

Table of Contents

Epidemiology

Common in TB-endemic countries.
One of the most common causes of ring-enhancing lesions in India.
More common in:

Children
Young adults
HIV-positive patients
Immunosuppressed individuals

May occur despite absence of active pulmonary TB.

Frequency of systemic TB

Evidence of extracranial TB is found in only:30–50% of cases

Thus absence of pulmonary TB does not exclude CNS tuberculoma.

Types of CNS Tuberculoma

Intracranial Tuberculoma-Most common

Locations:Frontal lobe,Parietal lobe,Cerebellum,Brainstem,Basal ganglia

Spinal Tuberculoma

Can occur:Intramedullary,Intradural extramedullary,Extradural

Rare (<5%)

Staging

Feature	Non-Caseating Tuberculoma (Early Stage)	Caseating Tuberculoma with Solid Center	Caseating Tuberculoma with Liquefied Center	Calcified Tuberculoma (Healed Stage)
Histology	Granulomas with no central necrosis	Caseating granuloma with solid center	Caseating granuloma with liquefaction	Inactive calcified granuloma
T1 MRI	Iso/hypointense	Iso/hypointense with hyperintense peripheral rim	Iso/hypointense with hyperintense peripheral rim	Iso/hypointense
T2 MRI	Hyperintense	Hypointense center (hallmark)	Hyperintense peripheral ring with hyperintense/liquefied center	Hypointense
FLAIR	Hyperintense	Hyperintense	Predominantly hyperintense	Hypointense
DWI	No restriction	Usually no restriction	Variable/heterogeneous hyperintensity; may show partial restriction	No restriction
Post-Gadolinium Enhancement	Homogeneous enhancement	Homogeneous or ring-like enhancement	Ring enhancement	No enhancement
MR Spectroscopy	Lipid peak may be present	Prominent lipid peak	Prominent lipid peak	Usually absent
Perilesional Edema	Mild–moderate	Moderate–marked	Marked	Minimal or absent
Differential Diagnosis	Glioma, demyelination	Neurocysticercosis	Brain abscess, metastasis, glioblastoma	Calcified NCC
Clinical Significance	Active granuloma	Most common form of tuberculoma	May behave as a space-occupying lesion	Residual healed disease
Exam Pearl	Homogeneous enhancement	T2 hypointense center strongly favors tuberculoma	Ring enhancement + lipid peak suggests tuberculoma over abscess	Known as “Tuberculoma en cocarde”

Clinical Features

Presentation depends upon:Size—Number—Location—Edema—Hydrocephalus

Clinical Feature	Details / Cause
Headache (Most Common Symptom)	Usually due to raised intracranial pressure (ICP), perilesional edema, mass effect, or associated hydrocephalus. Often progressive and persistent.
Seizures (Very Common)	Particularly common with supratentorial lesions. May present as focal seizures, focal-to-bilateral tonic-clonic seizures, or generalized tonic-clonic seizures. Can be the presenting manifestation.
Focal Neurological Deficits	Depend on lesion location and surrounding edema. Manifestations include hemiparesis, aphasia, visual field defects, cranial nerve palsies, sensory deficits, and focal cortical dysfunction.
Raised Intracranial Pressure (ICP)	Features include headache, vomiting, papilledema, altered sensorium, sixth nerve palsy, and in severe cases brain herniation. Usually occurs with large lesions, marked edema, or obstructive hydrocephalus.
Cerebellar Tuberculoma	Causes ataxia, dysmetria, intention tremor, nystagmus, gait imbalance, and impaired coordination. Large lesions may produce obstructive hydrocephalus.
Brainstem Tuberculoma	Produces long tract signs (hemiparesis, hyperreflexia, Babinski sign), cranial neuropathies (III, VI, VII, IX, X nerve involvement), bulbar dysfunction, respiratory abnormalities, and carries a poorer prognosis.

Clinical Syndromes

Location	Manifestation
Frontal	Personality changes, seizures
Parietal	Sensory deficits
Temporal	Seizures, memory issues
Occipital	Visual defects
Cerebellum	Ataxia
Brainstem	Cranial nerve deficits
Basal ganglia	Hemiparesis

CSF analysis

If isolated tuberculoma:CSF may be normal.

If associated TB meningitis then :

Parameter	Finding
Protein	↑
Glucose	↓
Lymphocytes	↑
ADA	May rise

CT Scan—Isodense or Hyperdense Lesion with Ring Enhancement after contrast.Associated:Edema,Mass effect

MRI Brain—Investigation of Choice

MR Spectroscopy
Characteristic:Lipid Peak,Strongly suggests tuberculoma.
Reason:Mycobacterial cell wall lipids.
May also show:Reduced NAA,Increased choline.

Diffusion-Weighted Imaging (DWI)

Usually:No marked diffusion restriction
Helps distinguish from pyogenic abscess.
Pyogenic abscess:Strong diffusion restriction
Tuberculoma:Variable or absent restriction

Differential Diagnosis of Ring Enhancing Lesions

MAGIC DR(Mnemonic)

	Key Features / Typical Clues
Metastasis	Often multiple lesions located at the gray-white matter junction with marked vasogenic edema. Common primaries include lung, breast, melanoma, renal cell carcinoma, and colorectal cancer.
Abscess	Infectious lesion containing pus. Presents with fever, headache, focal deficits. MRI shows smooth thin ring enhancement with marked diffusion restriction on DWI.
Glioblastoma (GBM)	High-grade primary brain tumor. Typically a thick irregular ring-enhancing lesion with central necrosis, infiltrative margins, significant edema, and mass effect. Often crosses the corpus callosum (“butterfly glioma”).
Infarction (Subacute)	Subacute cerebral infarcts may demonstrate gyriform or ring enhancement due to blood-brain barrier breakdown. Clinical history and vascular territory distribution help diagnosis.
Contusion	Usually follows head trauma. Hemorrhagic lesions commonly involve frontal and temporal lobes. Ring enhancement may occur during healing. Associated traumatic findings are often present.
Demyelination (Tumefactive Demyelinating Lesion)	Large demyelinating plaque that mimics a tumor. Characteristically shows incomplete/open ring enhancement, relatively less mass effect, and may be associated with multiple sclerosis.
Radiation Necrosis	Occurs months to years after radiotherapy. Produces ring-enhancing lesions with surrounding edema and may mimic tumor recurrence. MR perfusion and spectroscopy help differentiation.
Tuberculoma (Common in India)	One of the most common causes of ring-enhancing lesions in TB-endemic regions. MRI often shows T2 hypointense core, thick ring enhancement, and lipid peak on MR spectroscopy.
Neurocysticercosis (NCC) (Common in India)	Most common parasitic CNS infection. Typically small (<20 mm) ring-enhancing lesions, often multiple. Presence of a scolex is diagnostic. Surrounding edema varies with stage.

Tuberculoma vs Neurocysticercosis

Feature	Tuberculoma	Neurocysticercosis
Size	>20 mm often	Usually <20 mm
Edema	Marked	Mild
MRS	Lipid peak	Absent
Scolex	Absent	Present
T2 center	Hypointense	Hyperintense
Number	Solitary often	Multiple often
Calcification	Late	Common

Tuberculoma vs Pyogenic Abscess

Feature	Tuberculoma	Abscess
Fever	Less common	Common
DWI	Variable	Marked restriction
Wall	Thick irregular	Smooth thin
MRS	Lipid peak	Amino acid peak
AFB	May be positive	Negative

Definitive Diagnosis

Histopathology

Gold standard

Shows:

Caseating granulomas
Langhans giant cells

However biopsy is often avoided when imaging and clinical findings are typical.

Paradoxical Tuberculoma

Definition

Appearance of new tuberculoma or enlargement of existing tuberculoma after starting ATT.

Occurs despite:

Clinical improvement
Effective therapy

Mechanism

Immune reconstitution

↓

Enhanced inflammatory response

↓

Expansion of granuloma

Timing

Usually:2 weeks–6 months after ATT

Common in:

HIV
TB meningitis

Management

Same regimen as TB Meningitis.

Neurosurgical Management

Indications:

Diagnostic uncertainty
Large posterior fossa lesion
Obstructive hydrocephalus
Severe mass effect
Failure of medical treatment

Procedures:

Stereotactic biopsy
Excision
VP shunt
ETV

Monitoring Response

Clinical

Headache improves
Seizures reduce
Neurological deficits improve

Radiological

MRI every:2–3 months initially Then 6–12 monthly
Resolution may take: 12–24 months
Persistence of enhancement alone does not indicate treatment failure.

Complications

Neurological

Seizures
Hemiparesis
Cranial neuropathies
Cognitive impairment

Structural

Hydrocephalus
Herniation
Brainstem compression

Treatment Related

Drug hepatitis
Optic neuritis (ethambutol)
ATT resistance

Prognosis

Good with early diagnosis.

Factors associated with poor outcome:

Brainstem lesions
Multiple lesions
Hydrocephalus
Delayed treatment
HIV infection
Drug-resistant TB