Granulomatous diseases of the central nervous system

Insights into Magnetic Resonance Imaging Findings in Central Nervous System Paracoccidioidomycosis: A Comprehensive Review

Paracoccidioidomycosis (PCM) is a infection caused by the thermodimorphic fungus Paracoccidioides spp. (P. lutzii and, mainly, P. brasiliensis). This infection predominantly affects rural male workers aged between 30 and 50 years old who deal with soil on daily activities. Clinically, the disease is classified as acute/subacute phase, which evolves rapidly, secondary to dissemination of the fungus through to the phagocytic-mononuclear system, leading to fever, weight loss, and anorexia, associated with hepatosplenomegaly and lymphadenopathy, which can be complicated with suppuration and fistulization; and chronic phase, which corresponds to 74% to 95% of symptomatic cases, with a common pulmonary involvement. Central nervous system involvement is almost always a characteristic of the chronic form. Inhalation is the most common route of primary infection, usually affecting the lungs, forming the primary complex. From the primary complex, hematogenic dissemination can occur to any organ, including the brain and spinal cord. Although PCM of the central nervous system diagnosis is usually based on histopathological analysis and the imaging features are not specific for PCM, computed tomography and magnetic resonance imaging can demonstrate evidences of granuloma, abscess, meningitis, or a combination of these lesions, contributing to a preoperative diagnosis, especially when considered in conjunction with epidemiology. In this article, we review the pathophysiology, clinical manifestations and imaging aspects of neuro-PCM.

Granulomatous Diseases of the Central Nervous System

PURPOSE OF REVIEW

To discuss the pathophysiology, key clinical features, necessary diagnostic evaluation, and current treatment regimens for granulomatous diseases of the central nervous system.

RECENT FINDINGS

The diagnosis and management of granulomatous disease of the central nervous system has been revolutionized by advances in diagnostic imaging. Nevertheless, tissue and/or cerebrospinal fluid (CSF) sampling remains necessary to establish the diagnosis in most cases. Establishing a specific diagnosis is critical because treatment selection needs to focus on the granulomatous process centering on either antibiotic or immunosuppressive agents. Particular for non-infectious granulomatous disease more aggressive immunotherapies may help in clinical outcome. There are multiple non-infectious and infectious etiologies for granulomatous disease of the central nervous system. Clinical manifestations result from local structural invasion of granulomas or granulomatous inflammation of the blood vessels and meninges. Rapid diagnosis and specific treatment is essential.

Spontaneous necrotizing granuloma of the cerebellum: a case report

Background

Intracranial necrotizing granulomatous space-occupying lesions are sparsely reported in literature. Variability in presenting symptomatology and radiographic features makes diagnostic work-up difficult.

Case presentation

This report presents the case of a 77-year-old female with sinusitis and fatigue who underwent an MRI revealing a posterior fossa lesion compressing the fourth ventricle. Subsequent contrast CT of the chest, abdomen, and pelvis was negative for primary malignancy. Histopathologic examination of the lesion following biopsy showed it to be a necrotizing granuloma in an antineutrophil cytoplasmic antibody (ANCA) negative patient. The most likely diagnosis was determined to be spontaneous necrotizing granuloma, a rare entity with only one previous report noted.

Conclusions

Spontaneous necrotizing granuloma of the CNS is a rare entity that represents an important differential consideration in the work-up of space occupying lesions of the CNS.

Medical treatment of brain aspergilloma followed by MRI: A case report

This is a brain aspergilloma case in an immunocompetent patient who suffered from a rare fungal infection transmitted from the mediastinum to the brain and eventually caused pancreatitis. This fungal infection affected the thalamus, hypothalamus, and extended to the midbrain. This case showed a good prognosis for the brain aspergilloma without need for any surgical intervention. The radiological documentation for the brain aspergilloma shows a positive response to a combination of voriconazole and Keppra.

The Role of Neurosurgery in the Treatment of Intracranial Tumor-Like Inflammatory Lesions

BACKGROUND

Different inflammatory diseases can manifest as intracranial lesions. They may be indistinguishable from intracranial neoplasms in the clinical setting, imaging studies, or laboratory studies. The value of surgery in the diagnosis and the treatment of such lesions is still unclear.

METHODS

A total of 3066 reports of histopathologic examinations over a 10-year period were reviewed. Forty patients with an inflammatory intracranial lesion were identified. Clinical, radiologic, and follow-up data were analyzed and the diagnostic and therapeutic value of surgery was assessed.

RESULTS

We identified 24 women and 16 men (mean age, 47 years). The diameter of the lesion varied between 1 and 5.5 cm (mean, 2.6 cm). The location of the inflammatory lesion was intracerebral supratentorial (n = 18, 45%), intrasellar/suprasellar (n = 5, 12.5%), cerebellar (n = 5, 12.5%), in the brainstem (n = 4, 10%), in the cerebellopontine angle (n = 3, 7.5%), meningeal (n = 3, 7.5%), and at other locations (n = 6, 15%). Seventeen patients underwent surgical removal of the mass lesion, whereas in 23 patients a biopsy was taken. The lesions were classified into 7 groups: specific (infectious) granuloma (n = 10, 25%), unspecific granuloma (n = 7, 17.5%), idiopathic inflammatory pseudotumor (n = 5, 12.5%), demyelinating lesions (n = 5, 12.5%) encapsulated hematoma (n = 4, 10%), organized cerebral infarction (n = 3, 7.5%), and vasculitis (n = 4, 10%). Surgery was judged as valuable in 35 patients (87.5%).

CONCLUSIONS

The differential diagnosis of intracranial inflammatory lesions involves a wide spectrum. Surgery has a diagnostic and/or therapeutic value in most entities and clinical circumstances. However, attention must be taken to avoid surgery without a therapeutic or diagnostic value for the patient.

[Clinical pathology of granulomatous inflammation : With special emphasis on the lungs and central nervous system]

CLINICAL ISSUE

Granulomatous diseases are not rare in routine daily diagnostics. Granulomas are an indication of a sufficiently functioning immune system. In the absence of granulomas, a possible immunodeficiency should also be considered (e.g. in tuberculosis) in the diagnostic procedure. Many types of diseases with different etiologies can cause granulomatous manifestations.

DIAGNOSTICS

Diagnostic procedures should be oriented to the clinical symptoms and should include blood analyses, radiography, especially computed tomography (CT) and magnetic resonance imaging (MRI) and sampling for histology or cytology. In the case of proven granulomatous inflammation an infectious etiology should first be excluded. The diagnosis of a granulomatous disease should always be confirmed by histopathology when possible.

ACHIEVEMENTS

In this study the origins and general histopathological classification of granulomatous diseases are presented. In addition to the most common granulomatous diseases, some special and rare forms are discussed, which should also be considered in the differential diagnostic process.

PRACTICAL RECOMMENDATIONS

The diagnosis of a granulomatous disease should always be made in an interdisciplinary cooperation and requires close collaboration between radiologists, internists, pathologists and specialists in laboratory parameters.

Parasitic and rare spinal infections

The imaging features of spinal parasitic diseases and other rare infections are herein discussed. These diseases are distributed worldwide, with increased prevalence in areas with poor sanitary conditions and in developing countries. In nonendemic areas, sporadic cases may occur, consequent to increased international travel and immunocompromising conditions. Infectious diseases are usually treatable, and early detection is often crucial. A thorough comprehension of the imaging patterns associated with the clinical features, epidemiology, and laboratory results allows the radiologist to narrow down the options for differential diagnosis and facilitates the timely implementation of appropriate therapies.

Magnetic resonance imaging in fungal infections of the brain

An invasive fungal infection is a rare disease that can occur in otherwise healthy individuals. Fungi themselves are universal, and they are overall harmless organisms that cause at most a self-limiting disease in the general population. Immunocompromised individuals, whether iatrogenically, genetically, or acquired, present a group who are especially susceptible to a life-threatening disease from a normally innocuous pathogen. Fungi are normally inhaled and are cleared by pulmonary defense mechanisms in immunocompetent hosts. Invasion begins when these mechanisms fail in depressed immunity. Through bypassing of the pulmonary immune system, fungi can spread hematogenously. Fungal infections of the central nervous system are the most common extrapulmonary manifestation after fungal inhalation. Other risk factors of fungemia include prolonged indwelling catheters, maxillofacial infections, uncontrolled diabetes mellitus, systemic antibiotics, implanted neurosurgical devices, and intravenous drug abuse. Thus, other than direct inoculation via surgical complications or open trauma, central nervous system fungal infections are almost never primary.

Neuroparacoccidioidomycosis (NPCM): magnetic resonance imaging (MRI) findings

OBJECTIVE

To describe the magnetic resonance imaging (MRI) patterns of the central nervous system (CNS) involvement by neuroparacoccidioidomycosis (NPCM).

METHODS

Between January 1999 and March 2011, a review of MRI data analysis from 8 cases of NPCM was performed. The following MRI characteristics were examined by an experienced neuroradiologist: topography of lesions, aspects on T1- and T2-weighted images (WI), contrast enhancement, diffusion and spectroscopy.

RESULTS

All patients had evidence of paracoccidioidomycosis infection outside the nervous system. Regarding CNS involvement, five patients had only supratentorial lesions; three had infra- and supratentorial ones. Meningeal extension occurred in three patients. The lesions were predominantly hyperintense on T1WI. At T2WI, a hypointense component was present in five cases as well as a perilesional abnormal white matter. A ring-enhancement pattern was seen in five cases. Spectroscopy was performed in three patients and showed an increased lipid peak in all of them. In one case, there was also an increased choline peak.

CONCLUSION

NPCM is rare, and MRI may help its differentiation from other inflammatory lesions. However, the presence of active infection outside CNS and some imaging characteristics should point to this diagnosis.

Imaging of spine infection

This article reviews the imaging and relevant clinical details of infection of the extradural spine. Spine infections are increasing in incidence and in frequency of diagnosis. They are clinically important despite their relative rarity, because they may be life-threatening, and because early diagnosis leads to improved outcomes. The focus is on pyogenic spondylodiscitis. The also typically pyogenic conditions of epidural and subdural abscess, facet joint infection, and pyomyositis are discussed. Nonpyogenic, granulomatous infections are also addressed. Magnetic resonance imaging is emphasized. The radiologist's role in performing minimally invasive sampling procedures is highlighted.

Parasitic diseases of the central nervous system

This article reviews the characteristic imaging appearances of parasitic diseases of the central nervous system, including cysticercosis, toxoplasmosis, cystic echinococcosis, schistosomiasis, amebiasis, malariasis, sparganosis, paragonimiasis, and American and African trypanosomiases. Routine precontrast and postcontrast MR imaging helps in localization, characterization, delineation of extension, and follow-up of the parasitic lesions. Moreover, recently developed tools, such as diffusion, perfusion, and MR spectroscopy, help to differentiate parasitic diseases of the central nervous system from simulating lesions. Combining imaging findings with geographic prevalence, clinical history, and serologic tests is required for diagnosis of parasitic diseases of the central nervous system.

Disseminated intracranial tuberculoma mimicking neurocysticercosis

Intracranial tuberculoma and neurocysticercosis (NCC) are the most frequent granulomatous infections in the central nervous system. Here we report a 41-year-old man with disseminated intracranial tuberculoma mimicking NCC. The patient complained of relapsing vertigo and vomiting consistent with Bruns syndrome. Serum antibodies against cysticercosis were positive. Magnetic resonance imaging (MRI) of the brain showed multiple disseminated ring-enhanced lesions. An initial diagnosis of NCC was made based on clinical signs and MRI. However, during antiparasitic treatment, the patient exhibited fever, meningitis signs, and positive cerebrospinal fluid findings for tuberculosis. The diagnosis was therefore corrected as tuberculoma. After three months of antituberculous treatment, the patient recovered clinically and on MRI. Our results highlight the importance of differential diagnosis of these two diseases in the early stage.

Autoimmune hypophysitis: expanding the differential diagnosis to CTLA-4 blockade

Autoimmune hypophysitis is an increasingly recognized disorder that enters in the differential diagnosis of nonfunctioning pituitary masses. The differential diagnosis of these conditions is challenging because of similar clinical presentations and radiological signs. This review describes the essential features of hypophysitis and the other nonfunctioning pituitary masses. It also emphasizes a recently described feature of hypophysitis: its appearance with unexpectedly high frequency in patients receiving treatments that abrogate the function of cytotoxic T lymphocyte antigen 4.

Relevant imaging findings of cerebral aspergillosis on MRI: a retrospective case-based study in immunocompromised patients

The aim of the study was to assess neuroimaging patterns of cerebral aspergillosis with magnetic resonance imaging (1.5 T). The clinical and imaging data of nine patients were reviewed. Patients were included in the study if the diagnosis of aspergillosis was confirmed by either biopsy, autopsy, aspergillus antigen determination and/or neuroradiological and clinical response to specific treatment. Four patients had single or multiple abscesses presenting as ring-enhancing lesions on T1-weighted images, hypointensity of the ring on T2-weighted MR images and low to high signal intensity on diffusion-weighted imaging. Four patients had single or multiple infarctions affecting all compartments of the brain with hyperintensities on T2-weighted images in three of four patients, irregular parenchymal contrast enhancement in all patients and hemorrhagic transformation of the infarcted parenchyma in one patient. Diffusion-weighted images were positive in all ischemic areas. One patient with paranasal sinusitis developed a mycotic aneurysm of the internal carotid artery. Cerebral aspergillosis presents three principal neuroimaging findings: areas consistent with infarction; ring lesions consistent with abscess formation following infarction; and dural or vascular infiltration originating from paranasal sinusitis or orbital infiltration. Recognition of these patterns in cerebral aspergillosis may lead to more timely and effective diagnosis and treatment.