Olfactory Groove Meningioma Mimicking Late-Life Depression: A Case Report

Late-life depression presenting with atypical features, progressive functional decline, behavioral changes, or poor response to treatment should prompt consideration of secondary causes. Olfactory groove meningiomas are slow-growing anterior skull base tumors that may remain clinically silent for prolonged periods and may present primarily with neuropsychiatric symptoms due to frontal lobe involvement. We report the case of a 64-year-old woman with a progressive depressive presentation characterized by marked functional decline, apathy, abulia, behavioral disinhibition, impaired insight, and executive dysfunction. Symptoms were initially interpreted as a primary depressive disorder in the context of bereavement and were poorly responsive to psychopharmacological treatment. Neuroimaging revealed a large extra-axial anterior skull base mass centered on the olfactory groove, measuring approximately 63 mm in maximum diameter, with homogeneous contrast enhancement, marked mass effect on the frontal lobes, and extensive vasogenic edema. The patient underwent surgical resection in January 2024. Histopathological examination confirmed a World Health Organization grade 2 olfactory groove meningioma, with brain invasion and spontaneous necrosis. Postoperative imaging showed a small probable residual lesion, and the patient subsequently underwent adjuvant radiotherapy with 60 Gy in 30 fractions using volumetric modulated arc therapy. Follow-up imaging demonstrated a slight reduction in the residual lesion. Clinically, the patient showed postoperative improvement, with preserved orientation and language functions, no focal neurological deficits, and a return to functional independence in daily life, although residual anosmia and non-specific orthostatic symptoms persisted. This case illustrates a strong clinical association between a large olfactory groove meningioma and a late-life neuropsychiatric presentation initially interpreted as depression. Such tumors should be considered when apparent late-life depression is accompanied by progressive functional deterioration, behavioral disinhibition, impaired insight, executive dysfunction, or poor response to adequate psychiatric treatment. Neuroimaging should be considered in these presentations to identify potentially treatable structural brain lesions.