Imaging of tuberculosis. III. Tuberculosis as a mimicker of brain tumour

Central Nervous System Tuberculoma in the Corpus Callosum Mimicking a Butterfly Glioma: Literature Review of Radiological Findings and Our Experience

Context:

Central nervous system (CNS) tuberculoma is the most common form of intracranial parenchymal tuberculosis (TB) which accounts for approximately 40% of misdiagnosed brain lesions mimicking intracranial tumors. The most common sites are the cerebral hemispheres, basal ganglia, cerebellum, and brainstem.

Materials and Methods:

Radiological findings of corpus callosum tuberculomas have been described and set in relation with the available literature.

Results:

Corpus callosum tuberculomas are extremely rare, with only five cases reported in the current literature. Even though isolated CNS tuberculoma of the corpus callosum without systemic TB in immunocompetent patients occurs rarely, as in our case, it should be considered in the differential diagnosis of solitary corpus callosum lesions.

Conclusions:

Careful evaluation of the neuroradiological images with adequate clinicoradiological correlation allows for accurate diagnosis and ensures the proper and timely care.

Magnetic resonance imaging of infectious meningitis and ventriculitis in adults

Magnetic resonance imaging findings of meningitis are usually nonspecific with respect to the causative pathogen because the brain response to these insults is similar in most cases. In this article, we will use a few representative cases to describe the characteristic magnetic resonance findings of meningitis and its complications, including ventriculitis.

Cystic glioblastoma multiforme masquerading as a cerebral tuberculoma

Glioblastoma multiforme (GBM) is by far the most common and most aggressive malignant neoplasm of the primary brain tumours. It arises from the astrocytes and classified as WHO grade 4 astrocytoma. Diagnosis of GBM is sometimes difficult as radiological picture sometimes mimic with cerebral tuberculoma. In both the cases contrast-enhanced CT may show similar finding of a mass lesion with a hypodense centre surrounded by a ring of enhancement and any cyst if present. In the present case, a 45-year-old male patient presented with seizures and headache, a provisional diagnosis of tuberculoma was made on the basis of clinical and CT findings. However, on grounds of suspicion the patient was operated and fluid from the cyst was sent peroperatively for cytopathological examination which suggested the diagnosis of cystic GBM. This helped the surgeon to do maximum debulking of the tumour. Diagnosis was further confirmed by histopathology.

Central nervous system tuberculosis

Tuberculosis (TB) has shown a resurgence in nonendemic populations in recent years and accounts for 8 million deaths annually in the world. Central nervous system involvement is one of the most serious forms of this infection, acting as a prominent cause of morbidity and mortality in developing countries. The rising number of cases in developed countries is mostly attributed to factors such as the pandemic of acquired immunodeficiency syndrome and increased migration in a globalized world. Mycobacterium TB is responsible for almost all cases of tubercular infection in the central nervous system. It can manifest in a variety of forms as tuberculous meningitis, tuberculoma, and tubercular abscess. Spinal infection may result in spondylitis, arachnoiditis, and/or focal intramedullary tuberculomas. Timely diagnosis of central nervous system TB is paramount for the early institution of appropriate therapy, because delayed treatment is associated with severe morbidity and mortality. It is therefore important that physicians and radiologists understand the characteristic patterns, distribution, and imaging manifestations of TB in the central nervous system. Magnetic resonance imaging is considered the imaging modality of choice for the study of patients with suspected TB. Advanced imaging techniques including magnetic resonance perfusion and diffusion tensor imaging may be of value in the objective assessment of therapy and to guide the physician in the modulation of therapy in these patients.

Magnetic resonance imaging in central nervous system tuberculosis

Tuberculosis (TB) in any form is a devastating disease, which in its most severe form involves the central nervous system (CNS), with a high mortality and morbidity. Early diagnosis of CNS TB is necessary for appropriate treatment to reduce this morbidity and mortality. Routine diagnostic techniques involve culture and immunological tests of the tissue and biofluids, which are time-consuming and may delay definitive management. Noninvasive imaging modalities such as computed tomography (CT) scan and magnetic resonance imaging (MRI) are routinely used in the diagnosis of neurotuberculosis, with MRI offering greater inherent sensitivity and specificity than CT scan. In addition to conventional MRI imaging, magnetization transfer imaging, diffusion imaging, and proton magnetic resonance spectroscopy techniques are also being evaluated for better tissue characterization in CNS TB. The current article reviews the role of various MRI techniques in the diagnosis and management of CNS TB.

Revisiting the CNS Tuberculosis with Emphasis on Giant Tuberculomas and Introducing the “Outer Rim Excrescence Sign”

Central nervous system tuberculosis is a leading cause of morbidity and mortality in developing countries with Mycobacterium tuberculosis as the main etiological agent. Classical imaging findings pose no problem for diagnosis of CNS tuberculosis. Cases of giant or solitary ring enhancing lesions are increasing which mimic other infectious and noninfectious pathologies. This is a retrospective study of 40 patients (28 male and 12 female) of either surgically or clinically proven CNS tuberculosis. Solitary tuberculomas (ring or solid enhancing) were seen in 19 patients. Four patients showed presence of two to three lesions and the lesion more than one centimeter size was categorized as ‘giant tuberculoma’. Multiple lesions with other associated findings were noted in 21 patients. Total 33 patients showed solitary or multiple ring enhancing lesions. Seven patients showed solid enhancing lesions (giant tuberculoma). The “Outer rim excrescence sign” was noted in a total of 16 patients. Both brain and spinal tuberculosis was noted in six patients. Seven patients presented with meningitis and hydrocephalous which is considered as the most common manifestation in the literature. Spinal leptomeningeal involvement was seen in five patients, whereas intramedullary cord tuberculomas were noted in four patients. Profound T2W hypointensity is a reliable predictor for giant tuberculomas with intense contrast enhancement, especially in deep locations. ‘Outer rim excrescence’ sign may contribute in cases of ring and solid enhancing lesions, however it requires further comprehensive study with MT Imaging and MR Spectroscopy to be recorded as a differentiating feature.

CT features of tuberculous intracranial abscesses in children

BACKGROUND

Intracranial tuberculous (TB) abscesses still cause a diagnostic dilemma on both CT and MRI as they may mimic neoplasms. Recognition of TB abscesses may prompt further imaging and appropriate trial of therapy, and may reduce the need for biopsy.

OBJECTIVE

To report the CT features of eight intracranial TB lesions in children initially diagnosed as neoplasms and eventually treated as TB abscesses.

MATERIALS AND METHODS

We undertook a 3-year retrospective review of children with an initial CT diagnosis of intracranial neoplasm who were subsequently diagnosed as having TB abscesses.

RESULTS

Eight patients out of 60 with an initial diagnosis of a neoplasm on CT were misdiagnosed and were ultimately determined to have TB abscesses after biopsy or a trial of anti-TB therapy. The most consistent constellation of findings for the lesions were low density (n = 5), ring enhancement (n = 8), cerebral hemisphere location (n = 7), mass effect (n = 6), surrounding oedema (n = 5) and absence of a soft-tissue-density mass (n = 8).

CONCLUSION

In endemic regions, intracranial lesions with these appearances on CT should undergo further imaging and possibly a trial of anti-TB therapy before considering biopsy.

Modern imaging of tuberculosis in children: thoracic, central nervous system and abdominal tuberculosis

Tuberculosis (TB) can affect any organ in the body. Children are a high-risk group for contracting the disease and pose a constant challenge to clinicians with regard to making a definitive diagnosis. Radiologists are playing a more active role in diagnosing TB, and armed with more accurate diagnostic investigations such as CT and MRI, they must face the cost implications as well as technical limitations. This review aims to guide the reader through the modern imaging techniques useful for diagnosing TB of the thorax, central nervous system and abdomen in children. The more specific features of each modality in the particular anatomical regions are highlighted.

Lymphomatoid granulomatosis in a renal transplant patient

Lymphomatoid granulomatosis is a rare angiocentric and angiodestructive pulmonary angiitis considered as a variant of the lymphoproliferative disorder group. Patients with organ transplantation are at an increased risk for post-transplant lymphoproliferative disorders secondary to their immunosuppression. However, lymphomatoid granulomatosis has rarely been described in patients with renal transplantation. It often presents with severe pulmonary signs. We describe a case whose initial presentation was an isolated VIth nerve palsy. We review the radiological and pathological findings and discuss the etiopathogenesis and therapeutic options of this particular lymphoproliferative disorder. With careful and stepwise reduction in her immunosuppression, our patient showed a complete disappearance of her lymphomatoid granulomatosis, and she is clinically well more than 3 years after the diagnosis, with good kidney function.

[Multiple gliomas. Illustrative cases of 4 different presentations]

Multiple gliomas are uncommon and may be classified according to: a) the time of presentation in early (at diagnosis) or late (during treatment); b) the characteristics of computed tomography or magnetic resonance imaging (CT/MRI) in multifocal (with evidence of spread) and multicentric (without evidence of spread). From 212 patients with histopathologic diagnosis of glioma evaluated from March/90 to September/99, 15 (7%) had multiple lesions. We describe 4 patients: early multicentric, late multicentric, early multifocal and late multifocal, with emphasis on characteristics of CT/MRI and possible differential diagnosis. The differential diagnosis of multiple lesions in the central nervous system includes mainly infectious/inflammatory diseases and metastasis, however multiple gliomas should always be considered, even in patients with known systemic cancer, as described by others. Considering that CT/MRI features are not definite, the diagnosis should always be confirmed by histopathologic examination.

Imaging of tuberculosis--experience from 503 patients. I. Tuberculosis of the chest

PURPOSE

To give an overview of 503 patients with tuberculosis (TB) and to describe the radiologic findings of chest TB.

MATERIAL AND METHODS

A total of 503 patients with proven TB were reviewed; 266 had chest involvement.

RESULTS

Lung lesions were demonstrated in 214 patients. Infiltrates in the basal parts of the lungs or pleural effusion were often primarily mistaken for viral or bacterial infections. Consolidations within the lungs and pleural thickening were sometimes indistinguishable from malignancy. Positive culture of the sputum without lung lesions was encountered in 12 cases. Enlarged mediastinal lymph nodes were demonstrated in 67 cases, 35 without lesions in the lungs. The lymphadenopathy could be extensive, and both clinically and radiologically indistinguishable from lymphoma.

CONCLUSION

Due to the present increase in incidence of TB and the fact that TB can mimic many other conditions, it is important that both clinicians and radiologists have TB high on the list for differential diagnoses.