Magnetic resonance spectroscopy in ring enhancing lesions

Ruptured intraventricular tuberculous brain abscess mimicking cystic neoplasm: a case report

Central nervous system (CNS) tuberculosis is a potentially life-threatening condition that may manifest in different forms and simulate other pathologies. It rarely involves the ventricles and the occurrence of primary intraventricular tuberculous brain abscess (TBA) has exceptionally been reported. As far as we know, ruptured intraventricular TBA has not been described before. An immunocompetent 56-years-old man was admitted for sub-acute intracranial hypertension with behaviour disorders. Cranial magnetic resonance imaging (MRI) showed a cystic lesion of the third ventricle containing fluid-fluid level with biventricular hydrocephalus and debris in the occipital horns. A ruptured cystic neoplasm was first considered. The patient underwent surgery via a right transcortical transventricular approach, combining both microscope and endoscope. The puncture of the lesion brought pus and the Ziehl-Neelson (ZN) staining demonstrated acid-fast bacilli. Intraventricular tuberculous abscess is an extremely rare condition that can take an unusual radiological appearance. This observation highlights the consideration of tuberculosis within the list of differential diagnosis of intraventricular cystic lesions in immunocompetent hosts.

Giant Tuberculomas of Brain: Rare Neoplastic Mimic

Objective

Tuberculosis continues to be a major infectious disease in developing parts of the world. Primarily central nervous system tuberculosis manifests as meningitis, tuberculoma, or a brain abscess; however, rarely it may manifest as a large neoplastic mass such as lesion known as giant tuberculoma. Especially in central parts of India, the incidence of giant tuberculoma is quite high in pediatric population that too in posterior fossa of brain. Often, they are wrongly reported as neoplastic masses on imaging. The objective of this study was to evaluate different imaging appearances of a giant tuberculoma.

Materials and Methods

In this prospective study, all cases of giant tuberculoma presenting to a large tertiary care center in central India for 2 years (duration 2016-2018) were imaged and followed up. A total of nine patients, six females and three males, aged 4-16 years were studied on a 3-Tesla Siemens magnetic resonance imaging (MRI) scanner.

Results

In total, nine patients were included with 11 giant tuberculomas. Of 11, eight were infratentorial and three were supratentorial in location. On T2-weighted image sequence, these lesions showed central hypointensity with a peripheral hyperintense rim. Most observed finding on T1-weighted image sequence was central isointensity with peripheral hyperintense rim. Advanced imaging sequences such as magnetic resonance spectroscopy and magnetization transfer were also applied.

Conclusion

To the best of our knowledge, this is the largest series of giant tuberculoma in the pediatric population reported so far in any part of the world. We have described the various MRI imaging findings of this lesion in great details. Management of such rare cases and pertinent literature is reviewed briefly.

Awake surgery for isolated parenchymal degenerating neurocysticercosis - Case report and focused review of misdiagnosis of neurocysticercosis

Differential diagnosis of isolated single neurocysticercosis can be difficult, and management is controversial. We report here an original surgical strategy, and review previous studies reporting misdiagnosis, using the PRISMA guidelines. A 24-year-old man was admitted to our hospital for recent memory impairment, hypoesthesia of the right hand, and recurrent focal seizures without loss of consciousness. Brain MRI revealed a single ring-enhancing parenchymal lesion in the left superior postcentral gyrus, with large perilesional edema. Since exhaustive systemic exploration was negative, surgical resection of the lesion was decided on in a multidisciplinary team meeting. To preserve eloquent brain areas, surgery was performed in awake condition. It allowed complete resolution of clinical manifestations. The diagnosis of neurocysticercosis was confirmed on pathology. This case illustrates the utility of awake surgery in degenerating neurocysticercosis in functional areas, and emphasizes the importance of including it in differential diagnosis of cystic ring-enhancing brain lesions.

Magnetic resonance imaging spectrum of intracranial tubercular lesions: one disease, many faces

Tuberculosis is a devastating disease and has shown resurgence in recent years with the advent of acquired immunodeficiency syndrome. Central nervous system involvement is the most devastating form of the disease, comprising 10% of all tuberculosis cases. The causative organism, Mycobacterium tuberculosis, incites a granulomatous inflammatory response in the brain, the effects of which can be appreciated on magnetic resonance imaging (MRI), which can thus be used for diagnosis of the same. Neurotuberculosis can present in various patterns, which can be identified on MRI. The meningeal forms include leptomeningitis and pachymeningitis. Parenchymal forms of neurotuberculosis include tuberculoma in its various stages, tubercular cerebritis and abscess, tubercular rhombencephalitis, and tubercular encephalopathy. Each pattern has characteristic MRI appearances and differential diagnoses on imaging. Complications of neurotuberculosis, usually of tubercular meningitis, include hydrocephalus, vasculitis, and infarcts as well as cranial nerve palsies. Various MRI sequences besides the conventional ones can provide additional insight into the disease, help in quantifying the disease load, and help in differentiation of neurotuberculosis from conditions with similar imaging appearances and presentations. These can enable accurate and timely diagnosis by the radiologist and early institution of treatment in order to reduce the likelihood of permanent neurological sequelae.

Unique case of midbrain tuberculoma presenting as isolated inferior rectus palsy with nystagmus

Isolated brain stem tuberculoma constitutes about 5% of all intracranial tuberculomas. A case of isolated inferior rectus palsy with downbeat nystagmus due to presumed midbrain tuberculoma in an immunocompetent patient is described here. This report documents a rare entity of a combination of partial third nerve palsy with pupil involvement along with downbeat nystagmus.