autoimmuneparaneoplastic

Autoimmune paraneoplastic syndromes are immune-mediated conditions that occur in association with cancer, resulting from immune responses mounted against tumor antigens that cross-react with normal tissues. These syndromes can affect various organ systems, most commonly the nervous system, skin, and endocrine organs.

Pathophysiology involves both humoral and cellular responses. Tumors may express onconeural or other self-antigens that trigger antibodies or cytotoxic T cells directed against healthy tissues. In some cases, antibodies detected in serum or cerebrospinal fluid reflect an immune response to the tumor rather than direct tumor invasion.

The clinical spectrum is broad. Paraneoplastic neurological syndromes (PNS) include paraneoplastic cerebellar degeneration (often linked to Yo or PCA-1 antibodies), limbic encephalitis (anti-Hu, anti-Ma2), and opsoclonus–myoclonus. Paraneoplastic pemphigus is a severe autoimmune blistering disease associated with thymoma, lymphoma, or other malignancies. Endocrine and dermatologic paraneoplastic autoimmune phenomena also occur.

Diagnosis relies on recognition of a compatible clinical syndrome, testing for relevant paraneoplastic antibodies, and discovery of an underlying tumor through age-appropriate cancer screening. Management centers on treating the underlying cancer when feasible and modulating the immune response with therapies such as steroids, intravenous immunoglobulin, plasmapheresis, or rituximab. Symptomatic care is important, and long-term outcomes vary.

Prognosis is determined largely by cancer control and the extent of autoimmune organ involvement. Early detection improves potential for recovery, but some neurologic deficits may persist despite treatment. Ongoing research aims to improve antibody panels, tumor screening strategies, and targeted immunotherapies.