Malignancy and sensory neuropathy of unexplained cause: a prospective study of 51 patients.

OBJECTIVE To investigate the frequency of cancer developing in patients with peripheral sensory neuropathy of unexplained cause. DESIGN Prospective study. SETTING A neurologic unit in a general hospital. METHODS Following the diagnosis of neuropathy, we searched for occult malignancy. This search was repeated together with neurologic evaluations every 6 months thereafter. Patient recruitment began January 1, 1988, and ended December 31, 1995. The end point of the study was December 31, 1996. RESULTS In the study period, we observed 363 patients with peripheral sensory neuropathy. Of these, 53 patients without any identified cause of neuropathy were invited to participate in the study. Of the 53, 2 patients refused. Thus, we examined and followed up 51 patients, 42 men and 9 women, with a mean age of 64.5 years (range, 19-80 years). The range between the onset of neurologic symptoms and the diagnosis of neuropathy was 2 to 72 months (mean, 13.9 months). The follow-up period ranged from 14 to 94 months (mean, 51.4 months). In 18 patients (35.3%) (16 men and 2 women) whose mean age at diagnosis of neuropathy was 66.5 years. malignant growths were found 3 to 72 months (mean, 27.4 months) after the onset of the neuropathy. The cancer was in the liver in 4 patients (all had a primary hepatoma), the bladder in 3, the lymph nodes in 3 (all with non-Hodgkin lymphoma), the prostate gland in 2, the lungs in 2 (small cell lung cancer in both), the breast in 1, the pancreas in 1, the sublingual gland in 1, and the bone in 1 (a metastatic sarcoma). CONCLUSIONS More than one third of the patients with peripheral sensory neuropathy of unexplained cause developed cancer without any predominating type of malignancy.