INTRODUCTION: Memory impairment caused by bilateral hippocampal primitive brain tumor is rarely reported. Clinical and MRI features can mimic paraneoplastic limbic encephalitis (PLE), and the differential diagnosis between these 2 entities may be difficult. CASE REPORT: We report the case of a 42-year-old woman presenting with amnesia without neurologic focal signs at clinical examination. The neuroimaging features consisted of bilateral limbic hyperintensities on T2-weighted and FLAIR brain MRI. Despite exhaustive biologic and radiologic investigations, no specific etiology was found. The diagnosis of paraneoplastic limbic encephalitis was suspected, although antineuronal antibodies were negative and no cancer was detected after the first evaluation. Eight months after onset, the memory complaint of the patient increased along with disability in activities of the daily living, the neurologic examination slightly changed with frontal neurologic signs and the brain MRI showed a new cystic lesion in the left hippocampus with enhancement after contrast administration. The left temporal tumor was resected and the neuropathological examination was consistent with gliomatosis cerebri with a focal high grade astrocytoma. CONCLUSIONS: This case highlights the need to consider the possibility of infiltrative gliomatosis in patients presenting with features of paraneoplastic limbic encephalitis.
INTRODUCTION:Memory impairment caused by bilateral hippocampal primitive brain tumor is rarely reported. Clinical and MRI features can mimic paraneoplastic limbic encephalitis (PLE), and the differential diagnosis between these 2 entities may be difficult. CASE REPORT: We report the case of a 42-year-old woman presenting with amnesia without neurologic focal signs at clinical examination. The neuroimaging features consisted of bilateral limbic hyperintensities on T2-weighted and FLAIR brain MRI. Despite exhaustive biologic and radiologic investigations, no specific etiology was found. The diagnosis of paraneoplastic limbic encephalitis was suspected, although antineuronal antibodies were negative and no cancer was detected after the first evaluation. Eight months after onset, the memory complaint of the patient increased along with disability in activities of the daily living, the neurologic examination slightly changed with frontal neurologic signs and the brain MRI showed a new cystic lesion in the left hippocampus with enhancement after contrast administration. The left temporal tumor was resected and the neuropathological examination was consistent with gliomatosis cerebri with a focal high grade astrocytoma. CONCLUSIONS: This case highlights the need to consider the possibility of infiltrative gliomatosis in patients presenting with features of paraneoplastic limbic encephalitis.