Successful long-term treatment of paraneoplastic optic neuropathy with mycophenolate mofetil, prednisone, and plasmapheresis

Beyond Myelin Oligodendrocyte Glycoprotein and Aquaporin-4 Antibodies: Alternative Causes of Optic Neuritis

Optic neuritis (ON) is the most common cause of vision loss in young adults. It manifests as acute or subacute vision loss, often accompanied by retrobulbar discomfort or pain during eye movements. Typical ON is associated with Multiple Sclerosis (MS) and is generally mild and steroid-responsive. Atypical forms are characterized by unusual features, such as prominent optic disc edema, poor treatment response, and bilateral involvement, and they are often associated with autoantibodies against aquaporin-4 (AQP4) or Myelin Oligodendrocyte Glycoprotein (MOG). However, in some cases, AQP4 and MOG antibodies will return as negative, plunging the clinician into a diagnostic conundrum. AQP4- and MOG-seronegative ON warrants a broad differential diagnosis, including autoantibody-associated, granulomatous, and systemic disorders. These rare forms need to be identified promptly, as their management and prognosis are greatly different. The aim of this review is to describe the possible rarer etiologies of non-MS-related and AQP4- and MOG-IgG-seronegative inflammatory ON and discuss their diagnoses and treatments.

Vision Improvement after Osimertinib Treatment in Paraneoplastic Optic Neuropathy Associated with Lung Adenocarcinoma

Treatments for paraneoplastic optic neuropathy (PON), a tumor-related autoimmune disease, include immunosuppression, plasma exchange, and immunoglobulin therapies, as well as treatment of the underlying disease. Herein, we describe the clinical course of an older adult patient with PON whose loss of vision improved after switching between epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatments for cancer. A 76-year-old woman, who had been treated with gefitinib for lung adenocarcinoma for two years, presented with acute bilateral visual disturbances. Her decimal best-corrected visual acuity (BCVA) was 0.3 in the right eye (RE) and 0.7 in the left eye (LE). Slit-lamp examination and funduscopy showed no abnormal findings. Two weeks later, her BCVA decreased to 0.2 in the RE and 0.01 in the LE. Goldman's perimetry showed a defect in the lower nasal RE and extensive visual-field loss in the LE. Single-flash electroretinograms showed normal amplitudes. Magnetic resonance imaging revealed left optic neuritis and showed neither metastatic cancer nor multiple sclerosis. Pattern-reversal visual evoked potentials showed decreased P100 amplitudes in both eyes (BE). Based on a diagnosis of PON from clinical findings, methylprednisolone pulse treatment was administered. However, her BCVA became no light perception in BE two months after the first visit. Because the tumor tissue was found to be positive for the EGFR T790M resistance mutation by bronchoscopy, the EGFR-TKI treatment was changed to osimertinib, decreasing the size of the lung cancer lesions. Her BCVA improved to hand motion in BE. Her final BCVA was 0.01 in the RE, counting fingers 10 cm in the LE. She died at the age of 79 years. To our knowledge, no reports have shown improvement in BCVA in patients with PON after changing EGFR-TKI treatments. This report indicates that some patients may develop severe visual dysfunction without early treatment for the primary tumor.

Ocular Paraneoplastic Syndromes

Ocular-involving paraneoplastic syndromes present a wide variety of clinical symptoms. Understanding the background pathophysiological and immunopathological factors can help make a more refined differential diagnosis consistent with the signs and symptoms presented by patients. There are two main pathophysiology arms: (1) autoimmune pathomechanism, which is presented with cancer-associated retinopathy (CAR), melanoma-associated retinopathy (MAR), cancer-associated cone dysfunction (CACD), paraneoplastic vitelliform maculopathy (PVM), and paraneoplastic optic neuritis (PON), and (2) ectopic peptides, which is often caused by tumor-expressed growth factors (T-exGF) and presented with bilateral diffuse uveal melanocytic proliferation (BDUMP). Meticulous systematic analysis of patient symptoms is a critical diagnostic step, complemented by multimodal imaging, which includes fundus photography, optical coherent tomography, fundus autofluorescence, fundus fluorescein angiography, electrophysiological examination, and sometimes fundus indocyjanin green angiography if prescribed by the clinician. Assessment of the presence of circulating antibodies is required for diagnosis. Antiretinal autoantibodies are highly associated with visual paraneoplastic syndromes and may guide diagnosis by classifying clinical manifestations in addition to monitoring treatment.

Paraneoplastic Syndromes in Neuro-ophthalmology

PURPOSE OF REVIEW

This article discusses the varied types of paraneoplastic syndromes that commonly have neuro-ophthalmologic manifestations. Diagnostic considerations and therapeutic options for individual diseases are also discussed.

RECENT FINDINGS

Paraneoplastic syndromes can affect the afferent and efferent visual systems. Paraneoplastic syndromes may result in reduced visual acuity from retinal degeneration, alterations in melanocyte proliferation and uveal thickening, or acquired nystagmus. Ocular motor abnormalities related to paraneoplastic syndromes may present with symptoms from opsoclonus or from neuromuscular junction disease. Diagnosis remains challenging, but serologic identification of some specific antibodies may be helpful or confirmatory. Treatment, in addition to directed therapies against the underlying cancer, often requires systemic corticosteroids, plasma exchange, or immunosuppression, but some specific syndromes improve with use of targeted pharmacologic therapy.

SUMMARY

Diagnosis and therapy of paraneoplastic syndromes presenting with neuro-ophthalmic symptoms remain a challenge, but strategies are evolving and new approaches are on the horizon.