Anti-Hu antibody-associated paraneoplastic sensory demyElīnating polyneuropathy: case report

Up to 20% of oncological patients experience paraneoplastic syndrome that often predates the diagnosis of oncological disease. The pathogenesis is unclear and immunological response is believed to be the dominant factor. Unfortunately, these syndromes are often unrecognized, thus delaying early diagnosis and treatment. Case description: 65-years-old male first presented with burning pain in palms and soles, gait instability for the last month. Patient had smoked for 40 years but has now quit for the last 2 years. No other known comorbidities or medication use. On neurological examination glove-sock-type hyperaesthesia, sensitive peripheral ataxia in the legs, mild instability in the Romberg position, atactic gait was observed. The examination according to the polyneuropathy protocol was performed: nerve conduction study showed sensory-demyElīnating polyneuropathy, cytosis in cerebrospinal fluid was 6mkL with elevated IgG antibodies, in blood positive Anti-Hu onconeural antibodies was detected. Additional oncological screening was performed, but the only changes found were mediastinal lymphadenopathy in pulmonary CT scan. The patient received intravenous corticosteroids and plasmapheresis therapy with mild improvement of symptoms. Pulmonary CT scan was repeated: because of negative dynamics radiologists suspected a small-cell lung cancer. Additional examinations were performed, including video-assisted-thoracic surgery with lung segment resection and mediastinal biopsy, but no cytological and histological data on oncological disease were obtained. The patient was discharged from the hospital recommending outpatient PET/CT scan and pulmonary, abdominal CT scan after 3 months. Regardless of negative diagnostic tests, neurologists remained highly suspicious of neurologic paraneoplastic syndrome. Anti-Hu antibodies are very specific in oncological diseases and may be positive at a very early stage, even before the primary oncological process can be identified.