Peripheral nervous system alterations in small cell lung cancer. Clinico-pathological study

Small cell lung cancer (SCLC) is one of the most malignant tumors, especially often associated with nonmetastatic neurological disorders, corresponding to paraneoplastic neurological syndromes. The pathogenesis of which is unknown, however, mostly attributed to autoimmune processes. The aim of the study was to determine the pattern of the peripheral nervous system damage in SCLC. To provide further data contributing to the pathomechanism underlying these syndromes, immunocytochemical studies were initiated. Autopsy material was collected from 47 cases of SCLC. All these patients were examined clinically. The sections from the cervical, thoracic and lumbosacral segments of the spinal cord with spinal roots and dorsal root ganglia were taken. For immunohistochemistry following antisera were used: GFAP, MBP, IgG, IgM, ferritin, ubiquitin, alpha 1-antichymotrypsin, alpha 2-macroglobulin, C3 and C5b9 complement fractions. In 18 patients peripheral nervous system disturbances were diagnosed neurologically, 21 of cases presented neuromuscular disorders by emg. Among the nonmetastatic lesions most often a damage of dorsal root ganglia was observed (in 33 cases). Degeneration of the spinal roots was absent only in 8 cases. In 21 cases degenerative changes of motor neurons within anterior horn were present. In no case ubiquitin-positive inclusion bodies within the motor neurons could be found. In 8 cases extravasation of the IgG with diffuse labeling of the grey matter was observed. IgM immunoreactivity was markedly less frequently present, C5b9 complement fraction immunoreactivity was also confined only to cases with peripheral nervous system disturbances. Therefore, our preliminary data seem to confirm the participation of humoral immunity in paraneoplastic syndrome pathogenesis.