Abstract
A 54-year-old female with a known pulmonary adenocarcinoma presented with rapid memory and language disturbances, she was anosognostic and apathetic with a Mini-Mental State Exam score 24/30. MRI showed parieto-occipital cortical ribboning in diffusion-weighted sequences (DWI); cerebrospinal fluid (CSF) analysis found normal proteinorhachia (0,48 g/l), highly increased total tau (1481 ng/ml, N 116-370) and negative protein 14-3-3; testing for paraneoplastic antibodies (anti-Hu, Yo, Ri, CV2, PNMa2/Ta, amphiphysin) and antibodies associated with autoimmune limbic encephalitis (anti-NMDAR, AMPAR, CASPR2, LGI, GABABR) was negative.
EEGs were nonspecific. Intravenous methylprednisolone and immunoglobulins were ineffective.
The patient deceased with severe dementia, mutism and myoclonus, eight months after disease onset. A 69-year-old woman, with non-small cell lung carcinoma in remission, presented with delirium, myoclonus, and right-sided focal clonic seizures.
MRI showed right-sided frontal and possible caudate hyperintensities in DWI. EEG and both CSF protein level (0,46 g/l) and cell count were normal.
The same screening of paraneoplastic and limbic encephalitis associated antibodies as in case 1 was performed, also with negative results. Under sedation and valproate therapy, the patient's condition temporally improved; intravenous methylprednisolone and immunoglobulin treatment was inefficient.
Severe dementia, rigidity, and akinetic mutism developed. Death occurred after a disease course of two months.
Neuropathological examinations revealed leptomeningeal spread and cortical micrometastases of pulmonary carcinoma in both cases. Prion deposits were excluded using immunohistochemistry and western blot.