Oncogenic brain metazoan parasite infection

Abstract

Multiple observations suggest that certain parasitic infections can be oncogenic. Among these, neurocysticercosis is associated with increased risk for gliomas and hematologic malignancies. We report the case of a 71-year-old woman with colocalization of a metazoan parasite, possibly cysticercosis, and a WHO grade IV neuroepithelial tumor with exclusively neuronal differentiation by immunohistochemical stains (immunopositive for synaptophysin, neurofilament protein, and Neu-N and not for GFAP, vimentin, or S100). The colocalization and temporal relationship of these two entities suggest a causal relationship.

Figure 1

Initial brain MRI. (a), (b) Axial T1-weighted image with gadolinium, showing the enhancing intra- and periventricular left occipitotemporal mass. There is minimal mass effect. In (b) there is a suggestion of a “daughter cyst” lateral to the main lesion. (c) Sagittal T1-weighted image, with gadolinium, showing the lesion mostly within the occipital horn of the lateral ventricle. (d) Coronal T1-weighted image with gadolinium. The abnormal tissue involves the parenchyma around the ventricle as well as within the lumen.

Figure 2

H&E stained sections demonstrating the degenerate parasite after initial craniotomy. (a) The entire tissue is a complex of cysts, with no viable basophilic nuclei apparent at low power, including no inflammatory cells (original magnification 12.5x). (b) At higher magnification, the edge of the abnormal tissue has the typical appearance of a chitinous exoskeleton with a few surviving small nuclei beneath it (original magnification 400x).

Figure 3

Brain MRI at second admission. (a), (b) Axial T1-weighted image with gadolinium, showing a larger mass with peripheral enhancement compared to the original appearance of the lesion as seen in Figure 1. (c) Sagittal T1-weighted image with gadolinium, showing the larger lesion with a more substantial intraparenchymal component. (d) Coronal T1-weighted image with gadolinium also shows the enlarged lesion with greater mass effect.

Figure 4

Tissue removed from the second craniotomy. (a) The tumor is a densely cellular lesion composed mostly of small cells with small cell bodies (H&E, original magnification 200x). (b) A GFAP immunostain marks scattered single cells representing entrapped reactive astrocytes, 600x. (c) A Synaptophysin immunostain labels the cytoplasm of multiple tumor cells, surrounding their centrally-located nuclei (600x). (d) A neurofilament protein immunostain also labels the cytoplasm of many tumor cells as well as some processes from them (400x). (e) A Neu-N immunostain distinctly labels the nuclei of many tumor cells (600x).