CASE 13185 Published on 15.01.2016

Central Nervous System Tuberculosis(Tuberculomas) in Association with Pulmonary Tuberculosis

Section

Neuroradiology

Case Type

Clinical Cases

Authors

Suman Karki M.D

Manila Med Medical Center Manila; U.N Ave Taft Corner 1000 Manila, Philippines; Email: karkisuman123@yahoo.com
Patient

50 years, male

Categories
Area of Interest Lung, Neuroradiology brain ; Imaging Technique CT
Clinical History
A 49-year-old male presented with 2 weeks history of fever, cough, poor appetite, lethargy, headache and insomnia. Due to persistence of symptoms a consultation was sought. On the day of admission, the patient presented with altered sensorium and agitation.
Imaging Findings
Plain chest radiograph demonstrates bilateral upper lobe hazy infiltrates consistent with post primary tuberculosis.

Brain CT without and with IV contrast showed multiple, varisized mostly thick-walled peripherally enhancing nodules, some having central hypodensity scattered in both cerebral hemispheres. The finding is consistent with CNS tuberculomas.

High resolution chest CT shows a thick wall cavitary lesion at the right apical segment. There are also multiple nodular densities in both upper lobes. Several of these nodules exhibit tree in bud pattern. These findings are typical for post primary tuberculosis.
Discussion
In developing countries, tuberculosis remains a leading cause of morbidity and mortality. CNS involvement is thought to occur in 5% of patients with higher prevalence in immunocompromised patients, 15 % of which have AIDS related tuberculosis. It occurs in all age groups, however the majority of cases occur in younger individuals [1, 3].

CNS tuberculosis usually results from a hematogenous spread from distant systemic infection (pulmonary tuberculosis) or direct extension from local infection. It can manifest in different forms, including tuberculous meningitis, tuberculomas, tuberculous abscesses, tuberculous cerebritis, and miliary tuberculosis. The most common CNS parenchymal lesion of tuberculosis is, tuberculoma [1].

Tuberculomas are firm, avascular, spherical granulomatous masses. The inside of these masses may contain necrotic areas composed of caseous material, occasionally thick and purulent, in which tubercle bacilli can be demonstrated. It may occur either in isolation or in combination with extra-axial TB infection. The lesion may be solitary, multiple, or miliary and may be seen anywhere within the brain parenchyma, although it most commonly occurs within the frontal and parietal lobes [1, 3].

On CT, tuberculomas appears as low- or high-density and as rounded or lobulated masses. They show intense homogeneous or ring enhancement after contrast administration and have irregular or regular walls of varying thickness. The 'target sign' (a central calcification or nidus surrounded by a ring that enhances after contrast administration) occurs in one-third of patients, is suggestive of, but not pathognomonic of tuberculomas [1, 3].

Due to poor blood supply the injected contrast will accumulate slowly in the granulation tissue resulting in better enhancement in the delayed phase. Thus, 5 minutes delay was selected to obtain sufficient enhancement, and to achieve better display of the lesion size and margin outlines. Delayed acquisition at 5 minutes after contrast agent injection can improve precision and accuracy for imaging evaluations and clinical diagnosis and be the preferred imaging time [2].

In the light of pulmonary tuberculosis the diagnosis of CNS tuberculosis (tuberculomas) is easy. Stereotactic brain biopsy should be performed whenever the diagnosis of an intracranial tuberculoma is in doubt [3].

As in our case, typical ring enhancing lesions together with pulmonary findings of tuberculosis were helpful for making a final diagnosis of CNS tuberculosis (tuberculomsas) among the other entities.
Differential Diagnosis List
Central nervous system tuberculosis (tuberculomas) in association with pulmonary tuberculosis
Neurocyticercosis
Metastasis
Cerebral abscess
Final Diagnosis
Central nervous system tuberculosis (tuberculomas) in association with pulmonary tuberculosis
Case information
URL: https://www.eurorad.org/case/13185
DOI: 10.1594/EURORAD/CASE.13185
ISSN: 1563-4086
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