PMC6660454_01
Magnetic resonance imaging. A: Axial contrast-enhanced T1-weighted image demonstrates faint, uniform, peripheral enhancement of the lesions in the frontal and parietal lobes. B: Axial T2-weighted image demonstrates multiple round, circumscribed, T2 hyperintense lesions in the frontal and parietal lobes, without surrounding edema. C: Axial contrast-enhanced T1-weighted image of the lesion in the left cerebellum demonstrates faint, uniform, peripheral enhancement. D: Axial T2-weighted image of the posterior fossa demonstrates a 25 mm round, circumscribed, T2 hyperintense lesion in the left cerebellum without any surrounding edema.
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A subsequent magnetic resonance imaging (MRI) study of the brain with gadolinium contrast showed approximately 35 smoothly circumscribed cystic structures throughout the supra- and infra-tentorial brain parenchyma (Fig. 1).
A: Diffusely positive chromogranin immunohistochemical stain (a neuroendocrine tumor marker) of the left posterotemporal cystic brain lesion biopsy tissue. B: Hematoxylin-eosin (H&E) staining of the left posterotemporal cystic brain lesion biopsy specimen shows small epithelioid cells with abundant mitoses infiltrating into glial tissue, consistent with invasive malignancy.
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Six weeks after initial presentation, a brain biopsy of the left posterotemporal cystic lesion was performed, with pathology demonstrating metastatic neuroendocrine tumor (Fig. 2).