Acute focal demyelinating disease simulating brain tumors: Histopathologic guidelines for an accurate diagnosis

Abstract

The object of the present study was to determine the histopathological guidelines for accurate diagnosis of cases of acute focal demyelinating disease that simulates brain tumors. The surgical pathology of three such cases is assessed. Histopathological keys to the diagnosis of such cases are as follows. First, a pattern of sheets of atypical gemistocytic astrocytes in the white matter that show well-formed processes and that are adequately distanced from each other argues against a diagnosis of neoplasm. Second, uniform distribution of foamy macrophages aligned along axons, with occasional focal collections surrounding blood vessels and in the absence of any associated coagulative necrosis argues against the presence of a tumor. Third, perivascular chronic inflammatory infiltration, especially a mixture of lymphocytes and macrophages, favors the diagnosis of demyelination plaque. In such cases the lymphocytes will be predominantly T cells. Fourth, pleomorphic astrocytic proliferation with a lack of vascular endothelial proliferation should raise the suspicion that the lesion may not be a brain tumor. These diagnostic keys should be followed when diagnosing cases that are suspected to be demyelination processes rather than brain tumors. The presence of demyelination plaque should then be confirmed by imaging modalities such as staining with myelin-and axon-specific stains.

Dynamic perfusion CT in brain tumors

“…Using PCT, TDLs showed significantly lower BF, BV, and PS than HGGs [27]. These results are consistent with the observations that TDLs are characterized by normal or inflamed vessels and a lack of vascular proliferation while the latter is common in HGGs [26]. Primary brain lymphomas, brain metastases, and HGGs are malignant lesions that can appear similar to each other on MR images.…”

“…Tumefactive demyelinating lesions (TDLs) are solitary lesions greater than 2 cm that mimic HGGs on contrast-enhanced MR images [25], and can also be confused with HGGs on histopathology [26]. Differentiation of TDLs from HGGs may avoid unnecessary biopsy and resection of viable brain tissue.…”

Perfusion CT Imaging of Brain Tumors: An Overview

“…The situation could be confounded by the fact that TDLs can occasionally simulate neoplasms on histopathologic examination. 36,37 This has mostly been attributed to limited tissue samples such as those obtained from stereotactic brain biopsy. Biopsy of the gliotic margin may be pathologically misinterpreted at the edge of a glioma, and biopsy of the center of a TDL lesion may lead to the erroneous diagnosis of an infarct or necrotic neoplasm.…”

“…One of the important biologic differences between TDL and high-grade intracranial tumors is the presence of neoangiogenesis and vascular endothelial proliferation in the latter, whereas TDLs are characterized by intrinsically normal or inflamed vessels without evidence of neovascularity. 36,38,39 TDLs show lower PS and CBV compared with high-grade gliomas, and PCT can be used to differentiate the 2 entities (Fig 6). 40 Similarly, various vasculitis and angiopathies can rarely present as solitary or multiple masslike lesions, mimicking neoplasms on morphologic imaging.…”

A case of tumor-like inflammatory demyelinating disease with progressive brain and spinal cord involvement

“…[6][7][8] On images, TIDD and high-grade gliomas can both show contrast enhancement, perilesional edema, varying degrees of mass effect and central necrosis. 9 Enhancement in TIDD cases is thought to correlate with the degree of macrophage infiltration and related blood-brain barrier breakdown, which is a relatively early histological finding in cases of acute lesions.…”