Paraneoplastic encephalitis presenting as pure word deafness in a patient with small cell lung cancer

Abstract

Pure word deafness (PWD) is a rare neuropsychologic syndrome characterized by the inability to comprehend and repeat speech and defective writing to dictation with preserved ability to identify nonverbal sounds [1]. A 52-year-old right-handed man with a history of 105-pack-year smoking history presented with suddenonset difficulties understanding spoken language since 10 days before. Additionally, he had experienced two episodes of tingling in the right hemibody and auditory hallucinations (musical tones) that lasted for 30 s. Cranial nerves, strength, sensation, gait, coordination, and reflexes were intact. He was alert and oriented. Speech was fluent, and grammatically correct. Verbal and visual memory, praxis, right-left discrimination, finger identification, and executive function skills were within normal limits. He was able to recognize music and non-verbal sounds. Oral tests were altered, including yes/no questions, oral commands, and completion of sentences. Repetition was slightly altered. Nomination, calculation, reading aloud, and reading comprehension were conserved. He made no mistakes in writing spontaneously, copying, and answering written questions. Pure tone threshold audiometry, brainstem auditoryevoked potentials, and contrast-enhanced brain MRI revealed no abnormalities. EEG showed slow waves and sharp spikes in the left temporal region (T3, F7, T5). Blood tests were within normal limits. Cerebrospinal fluid (CSF) analysis showed increased cells (32 lymphocytes/ll, no malignant cells), oligoclonal bands with increased IgG and IgM, normal proteins (50 mg/dl), and normal glucose (84 mg/dl). These results were consistent with infectious or paraneoplastic encephalitis, hence, empirical treatment with ganciclovir 5 mg/kg/12 h, ceftriaxone 2 g/12 h, and metronidazole 500 mg/8 h was started. Gabapentin 800 mg/day was also started. A whole-body 18-fluoro-deoxy-glucose-positron emission tomography (FDG-PET) found hypermetabolic foci in the hilum of the right lung (SUVmax: 8), and the lower lobe of the left lung (SUVmax: 3.8). There was also decreased metabolism in the anterior-lateral area of the left temporal lobe, including the insular cortex, with spared primary language areas and primary auditory cortex, consistent with encephalitis (Fig. 1a). Thoracic CT scan disclosed a nodular adenopathy in the right hilum and a hypodense nodular lesion in the lingula. Cytologic examination of material obtained by endobronchial brushing revealed malignant cells consistent with small cell lung cancer (SCLC). CSF cultures and PCR for herpes simplex, varicella-zoster, and enteroviruses resulted negative, and antibiotic and antiviral treatment were withdrawn. Serum and CSF paraneoplastic panel (anti-Hu, anti-Yo, anti-Ri, anti-CV2, antiMa, anti-VGKC, anti-GAD, and anti-amphiphysin) resulted negative. He then received the first dose of chemotherapy. At discharge, episodes of tingling and hallucinations had remitted, but language disturbance remained. He subsequently received three additional cycles of chemotherapy and prophylactic holocraneal and thoracic radiotherapy. At 6-month follow-up, neuropsychological examination was normal except for slight J.-A. Palma I. Lamet M. Riverol (&) Department of Neurology, University Clinic of Navarra, 31008 Pamplona, Spain e-mail: mriverol@unav.es