Demyelinating disease simulating brain tumours: A histopathologic assessment of seven cases

Abstract

BACKGROUND: Demyelinating diseases can present as space occupying lesions with in the brain. It is clinically and radiologically difficult to differentiate them from primary neoplasms. Histopathologically they mimic astrocytic neoplasms closely and identifying these lesions correctly has a profound impact in treatment and prognosis of these patients. AIMS AND OBJECTIVES: The objective was to determine the histopathologic features of such acute focal demyelinating disease that clinically presented as brain tumors. MATERIAL AND METHODS: Seven cases were included for the study. Detailed histopathological examination including stains for myelin and axon were performed. The histopathological keys in arriving at the right diagnoses included a well demarcated lesion that contains uniform distribution of foamy macrophages in the absence of any associated coagulative necrosis, sheets of gemistocytic astrocytes in the white matter that show well-formed processes, perivascular chronic inflammatory cell infiltration and total absence of myelin with relative preservation of axons within these areas. CONCLUSION: The degree of suspicion (clinical, radiological and histopathological) should be high to diagnose these group of lesions. The above-mentioned diagnostic keys should help in arriving at the correct histopathological diagnoses of such cases.

Demyelinating Pseudotumour : A case report.

“…One study suggested that these lesions are not associated with necrosis [9], but a separate study demonstrated central necrosis within these lesions [4]. In our case, the lesion showed abundant necrosis.…”

“…In a retrospective review of 40 patients with biopsy or autopsy-proven demyelinating lesions, only three patients had minimal oedema and mass effect, while one patient had moderate oedema and severe mass effect on radiological imaging [3]. Three case reports describing cerebral demyelinating lesions also demonstrated conflicitng evidence in relation to the presence of mass effect surrounding these lesions on radiological imaging [4][5][6].…”

Inflammatory demyelinating pseudotumor with hemorrhage masquerading high grade cerebral neoplasm

“…Inflammatory demyelinating pseudotumor (IDMP) is a puzzle to clinicians, radiologists and pathologists due to many overlapping features (1,(3)(4)(5)7). Pathogenesis of IDMPs is not clear and it is different from multiple sclerosis and acute disseminated encephalomyelitis (9).…”

“…It is very difficult to differentiate these lesions from brain tumors as there is a considerable clinico-radiological overlap and it becomes nearly impossible to differentiate on routine cross sectional imaging when they present with hemorrhage or show complete rim enhancement (1,3,4,8). Subsequent relapse of symptoms and the presence of multiple abnormal signal intensity plaques, should raise suspicion of demyelinating pseudotumor (5).…”

“…Demyelinating pseudotumors are rare, benign, solitary intracranial space occupying lesions which masquerade brain neoplasms clinically, radiologically and histopathologically (1)(2)(3)(4)(5)(6)(7). It is very difficult to differentiate these lesions from brain tumors as there is a considerable clinico-radiological overlap and it becomes nearly impossible to differentiate on routine cross sectional imaging when they present with hemorrhage or show complete rim enhancement (1,3,4,8).…”