[Carcinomatous neuropathy: clinical and pathologic findings of sural nerve biopsy in 7 cases]

Sural nerve biopsy was done 7 cases of cancer patients associated with peripheral neuropathy. There were 3 cases of lung carcinoma and one each of pancreas adenoma, seminoma, sigmoid carcinoma and chondrosarcoma of the femur. The neurological features manifested themselves with sensory pattern of neuropathy associated with ataxia in one case, sensorimotor neuropathy in 3 cases, and idiopathic polyneuropathy, peripheral neuropathy with proximal myopathy and neuropathy with paraneoplastic cerebellar syndrome each in one case, 6 patients showed neuropathy before malignancy was discovered and only one patient had neuropathy after the onset of carcinoma. Sural nerve biopsy studied in all the 7 patients with light and electron microscope revealed no infiltration of carcinomatous cells in the sural nerve fascicles. There was severe loss of myelinated fibers and severely axonal degeneration in one patient. Another patient showed segmental demyelination (5.03 x 10(3)/mm2). There was evidence of both axonal degeneration and demyelination associated with moderate reduction in the number of the myelinated fiber density ranging from 1.02 to 4.35 x 10(3)/mm2. In 6 cases, mononuclear cells were seen in nerve fascicles under the electron microscope. The characteristic pathological findings, their relation with the duration and onset of the cancer and some ideas regarding the pathogenesis are discussed.