Encephalitis associated with carcinoma. Central hypoventilation syndrome and cytoplasmic inclusion bodies.

A case of encephalitis associated with a remote and occult oat cell carcinoma is presented in which the main clinical features were progressive dementia and central hypoventilation syndrome. The only significant anatomical lesions within the known anatomical substrate of respiration affected the locus caeruleus on both sides. It is speculated that the degeneration of the locus caeruleus was responsible for the central hypoventilation syndrome. Hitherto undescribed neuronal intracytoplasmic eosinophilic inclusions were found in an isolated lesion of the insular cortex. Electron microscopy failed to disclose viral particles in the regions of neuronal degeneration.