Paraneoplastic syndromes in ophthalmology

Paraneoplastic syndromes consist on systemic manifestations associated with certain cancers which are not a direct consequence of tumor invasion or its metastases. It is known that autoimmunity and autoantibody synthesis play an important role in its pathophysiology due to a process of molecular mimicry. Paraneoplastic syndromes in ophthalmology are rare, but it is important to recognize them clinically because in some cases symptoms preceded the diagnosis of an underlying neoplasia. Most frequently involved cancer is small cell lung carcinoma, but there is also a relationship with other tumor etiologies such as thymoma, gynecological tumors or neuroblastoma in children. Paraneoplastic syndromes with ocular involvement can be divided into those that affect the afferent visual pathway, such as cancer-associated retinopathy, melanoma-associated retinopathy, or paraneoplastic optic neuropathy; and the ones that affect the efferent visual pathway, such as bilateral tonic pupils, Myasthenia Gravis, Lambert-Eaton syndrome or paraneoplastic cerebellar degeneration. The presence of autoantibodies is helpful in clinical practice but negativity does not exclude this diagnosis. Although evolution and prognosis is linked to primary disease, in some cases specific treatment, usually immunosuppressive therapy, can help improving patients quality of life.