PMC4308089_01
Electroencephalography shows left temporal dysfunction. This electroencephalogram (EEG), performed with anterior temporal and standard 10-20 electrodes during the waking, drowsy, and sleeping states, is abnormal because of occasional left temporal theta slowing. These findings are suggestive of mild left temporal dysfunction. There are no definite epileptiform abnormalities.
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There were no definite epileptiform abnormalities (Fig. 2). These findings are suggestive of mild left temporal dysfunction.
Lesions in the temporal/parietal cortex and cerebellum show nodular enhancement and edema. Axial T2 (A) and FLAIR (B, C) MRI images show increased signal at the right cerebellum (A, arrows) and right parietal (B, arrows) and left temporal (C, arrows) lobes consistent with edema. Axial post-gadolinium contrast images show corresponding clusters of small (1-3 mm) enhancing nodules at the right cerebellum (D, arrows) and right parietal (E, arrows) and left temporal (F, arrows) lobes. These findings likely represent granulomatous tissue surrounding the eggs. The differential diagnosis based on these radiologic findings would include a spectrum of vasculitides, lymphomatoid granulomatosis, infection, and, less likely, granulomatous disease or tumor.
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Brain MRI imaging showed areas of abnormal T2 and FLAIR signal at the medial and lateral aspects of the anterior left temporal and right posterior temporal parietal lobes (with the left more affected than the right), as well as a similar small area of abnormality of the right cerebellum (Figs. 3A-C). After contrast administration, all these areas showed mottled nodular linear enhancement without significant mass effect (Figs. 3D-F).
Tissue smear and frozen section reveal extensive inflammatory infiltrates and necrosis in the temporal cortex. (A) Smear preparation of left temporal cortex biopsy showing vessels with perivascular inflammation (black arrows) and areas of necrosis. (B) Frozen section of left temporal cortex biopsy showing prominent collections of mononuclear cells (macrophage/histiocyte clusters) and scattered eosinophils concerning for granulomas (yellow arrows). Pathologic differential of this appearance includes infection (TB vs. schistosomiasis), vasculitis, and lymphomatoid granulomatosis.
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Initial intraoperative consultation with frozen section/smear evaluation showed collections of histiocytes concerning for granulomas, vascular involvement, and necrosis suspicious for an infectious process (Figs. 4A-B).
Extensive granulomas are present in the temporal cortex. (A) A paraffin section of the formalin-fixed temporal lobe biopsy shows reactive brain tissue extensively involved by prominent granuloma formation and reactive gliosis. (B) A magnified view of one granuloma pictured in the yellow box in (A) shows dense mixed inflammatory infiltrates comprised of eosinophils, plasma cells, and lymphocytes.
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Subsequent evaluation of paraffin-embedded permanent sections showed brain tissue with extensive granuloma formation and dense mixed inflammatory infiltrates comprised of eosinophils, plasma cells, histiocytes, and lymphocytes (Figs. 5A-B).
An infectious etiology: Schistosoma mansoni. (A) Magnification of the center of one of the granulomas reveals an egg with a refractile shell showing the pathognomonic acentric spine shape of Schistosoma mansoni. Reynolds' layer (R) has filled the spine but is not well defined with regard to the remaining egg shell. A single layer of squamous cells (von Lichtenberg's envelope) (L) is seen at the apex of the egg and is closely adherent to Reynold's layer. The envelope surrounds the developing miracidium (M) with multiple nuclei. Neutrophils and histiocytes adjacent to the egg highlight the smaller size of the schistosome nuclei in comparison to those in human cells. (The image is taken at 40 x without a condenser in order to increase refraction and highlight the contour of the egg shell. Bar = 10 mum.).
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Review of multiple tissue sections revealed refractile shell fragments at the center of each granuloma with occasional intact shells showing the pathognomonic acentric spine shape of S. mansoni (Fig. 6A).