Aggressive granular cell tumor of the neurohypophysis with optic tract edema and invasion into third ventricle

BACKGROUND: Granular cell tumors (GCTs) of the neurohypophysis are parasellar tumors arising from pituicytes in the neurohypophysis and are generally considered benign slow-growing tumors. We present a case of sellar GCT with aggressive features. CASE DESCRIPTION: A 70-year-old female presented with progressive vision impairment found to have bitemporal visual field defects. Subsequent magnetic resonance imaging (MRI) revealed a 2.9 cm × 2.5 cm × 2.5 cm parasellar mass with extension into the third ventricle and causing optic tract edema (OTE). Right frontotemporal orbital craniotomy was performed and the tumor was partially removed to decompress optic nerves. Pathology identified the tumor as granular tumor of the sellar region. The patient’s vision improved minimally after the surgery. Follow-up MRI after 3 months and 11 months showed stable left OTE. CONCLUSION: GCTs were thought to be benign tumors with slow growth, but they could potentially possess aggressive features and invade into surrounding structures as described in this case. OTE can be a rare MRI finding of GCTs. Only one case of GCT-related OTE has been reported in literature to our best knowledge.