PMC6884947_01
MRI findings of the granular cell tumor (yellow arrow). The lesion was hypointense on T2 image (a). It was enhanced homogeneously (b). The lesion invaded into the third ventricle (c) and caused optic tract edema (d, red arrow).
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F1
T1 and fluid-attenuated inversion recovery (FLAIR), hypointense on T2 [Figure 1a] with homogeneous enhancement [Figure 1b]. The mass was inseparable from the superior aspect of the optic chiasm which was displaced inferiorly. It extended superiorly into the inferior margin of the third ventricle [Figure 1c] and was closely abutting the superior aspect of the pituitary infundibulum. There was increased signal along bilateral optic tracts and visualized a portion of the optic chiasm particularly on the left side, suggesting optic tract edema (OTE) [Figure 1d].
Pathology findings. H & E stain demonstrated epithelioid to vaguely spindled cells with round to ovoid nuclei and granular eosinophilic cytoplasm (a, b). PAS stain highlighted the cytoplasmic granularity (c). Positive nuclear staining for thyroid transcription factor-1 (d).
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F2
The tumor consisted of epithelioid to vaguely spindled cells with round to ovoid nuclei and abundant granular eosinophilic cytoplasm [Figure 2a and b]. The periodic acid-Schiff (PAS) stain largely highlighted the cytoplasmic granularity [Figure 2c]. The tumor showed diffuse positive nuclear staining for thyroid transcription factor-1 (TTF-1) [Figure 2d] and weak, patchy staining for S-100 and glial fibrillary acid protein.