[Clinical and imaging characteristics of optic nerve tumors as the differencial diagnosis of optic neuritis]

Objective: To investigate the clinical and imaging features of optic nerve tumors that require differential diagnosis from optic neuritis. Methods: A retrospective case series study was conducted. Clinical data of patients diagnosed with optic nerve tumors from January 2017 to December 2021 at the Second Affiliated Hospital of Zhejiang University School of Medicine were collected. A total of 29 patients (39 eyes) with clinical and magnetic resonance imaging (MRI) findings similar to optic neuritis or optic neuropathy were included. There were 15 cases of optic nerve sheath meningioma (ONSM) (17 eyes), 4 cases of optic nerve glioma (ONG) (5 eyes), and 10 cases of infiltrative optic nerve lesions (ION) (17 eyes). All patients underwent best-corrected visual acuity (BCVA), anterior and posterior segment examinations, visual field examination, and orbital or cranial MRI examination. Patient data were observed and analyzed, treatment and follow-up information were recorded, and clinical and imaging features were summarized and compared with those of optic neuritis or optic neuropathy. Results: Among the 29 patients with optic nerve tumors, 10 were male and 19 were female, with an average age of (43.3±13.8) years and a range of 11 to 72 years. The follow-up time was 6.8 (2.0, 11.0) months, with a range of 1 to 33 months. Sixteen patients (21 eyes) with optic nerve tumors were initially misdiagnosed as having acute optic neuritis and showed poor response to steroid treatment. Of these, 9 cases (11 eyes) were ONSM, 4 cases (6 eyes) were ION, and 3 cases (4 eyes) were ONG. The diagnostic delay time was 7.1 (1.5, 12.0) months, with a range of 1 to 24 months. The main clinical symptoms of all affected eyes were acute vision loss in 23 eyes, slow vision loss in 5 eyes, transient blackouts in 4 eyes, and no obvious visual symptoms in 7 eyes. The median BCVA of all affected eyes was 0.1, ranging from light perception to 1.0. Fundus examination results showed optic disc edema in 34 eyes and normal optic disc in 5 eyes among the 39 eyes with optic nerve tumors. A total of 27 patients (33 eyes) completed visual field examinations, which revealed an enlarged physiological blind spot in 11 eyes, a concentric or tubular visual field contraction in 8 eyes, a diffuse decrease in light sensitivity in 7 eyes, an arcuate scotoma in 4 eyes, and a normal visual field in 3 eyes. All affected eyes completed orbital or cranial MRI examinations, which showed mild optic nerve thickening in 22 eyes, significant thickening in 6 eyes with distortion, and no significant thickening in 6 eyes. Contrast-enhanced T1-weighted imaging (T1WI) MRI showed optic nerve parenchymal thickening in 5 eyes, all of which were ONG, and 2 of them had optic nerve parenchymal enhancement. Optic nerve sheath thickening and enhancement without optic nerve parenchymal thickening or enhancement were observed in 28 eyes, including 17 eyes of ION and 11 eyes of ONSM. There were 6 eyes with no obvious optic nerve thickening, which were all ONSM, showing mild or significant thickening and enhancement of the optic nerve sheath without optic nerve parenchymal thickening or enhancement. Conclusions: Optic nerve tumors can present with ophthalmic clinical features similar to optic neuritis, such as optic disc edema, and demonstrate MRI findings that resemble those of optic neuritis. Therefore, differentiation between the two is crucial, based on differences in their natural course and response to steroid therapy.

Detecting changes in the blood flow of the optic disk in patients with nonarteritic anterior ischemic optic neuropathy via optical coherence tomography-angiography

Purpose

This study aimed to evaluate the changes in the blood flow of the optic disk in patients with nonarteritic anterior ischemic optic neuropathy (NAION) using optical coherence tomography-angiography (OCTA) and to investigate the relationship among the changes in the blood flow of the optic disk, visual field defect, peripapillary retinal nerve fiber layer (RNFL), and macular ganglion cell complex (mGCC).

Methods

This was a prospective observational case series study. A total of 89 patients (89 eyes) with NAION were included in this study. All patients underwent best corrected visual acuity (BCVA), slit-lamp and direct ophthalmoscopic examinations, color fundus photography, visual field test, and blood flow indicators of the radial peripapillary capillaries (RPC) including whole en face image vessel density (VD), peripapillary VD by OCTA, the peripapillary RNFL, and mGCC by spectral-domain optic coherence tomography (OCT). The changes of blood flow in the optic disk at ≤3, 4-8, 9-12, 13-24, and >24 weeks of the natural course of NAION were measured, and the relationship among the changes in the blood flow of the optic disk, visual field defect, peripapillary RNFL, and mGCC was also analyzed.

Results

The mean age of 89 patients with NAION was 56.42 ± 6.81 years (ranging from 39 to 79). The initial RPC whole en face image VD was significantly reduced after acute NAION (≤3 weeks) (F = 45.598, P < 0.001) and stabilized from the eighth week onward. Over the course of NAION, the superonasal RPC, superior mGCC, and superotemporal RNFL decreased mostly with time (F = 95.658, 109.787, 263.872, respectively; P < 0.001). Maximal correlations were found between superior mGCC and temporosuperior RPC in the NAION phase (R = 0.683, P < 0.01) and between superonasal RPC and superonasal RNFL (R = 0.740, P < 0.01). The mean defect was correlated with temporosuperior RPC (R = -0.281, P < 0.01) and superior mGCC (R = -0.160, P = 0.012).

Conclusion

Over the course of NAION, OCTA shows a tendency toward change in the retinal capillary plexus of the optic disk. OCTA is proved to be a practical and useful tool for observing papillary perfusion in NAION.

Serum and Cerebrospinal Fluid Testing in Optic Neuropathy Patients with Malignant Tumors

PURPOSE

To evaluate the value of serum and cerebrospinal fluid (CSF) testing in optic neuropathy (ON) patients with malignant tumors.

METHODS

Fourteen patients clinically diagnosed as ON with malignant tumors but without intracranial or orbital mass in MRI were included in this study. Detailed medical records including medical history, complete ophthalmic examination, colour fundus photography, visual field test, orbital MRI examination, serum and CSF testing data were collected and analyzed. The diagnosis of paraneoplastic optic neuropathy (PON) based on the 2004 recommended criteria of the paraneoplastic syndrome- Euronetwork consortium for paraneoplastic neurological disorders, and current adaption for neuropathies. All patients underwent serum tests for pathogens and autoantibodies including antinuclear antibodies, anticardiolipin antibodies, antineutrophil cytoplasmic antibodies, AQP4-Ab and MOG-Ab, as well as CSF tests for malignant cells under microscope. Serum paraneoplastic antibodies were detected in PON patients. Monkey cerebellar tissue-based assay was used to detect unknown serum anti-neuron antibodies in PON patients with negative paraneoplastic antibody testing results.

RESULTS

Fourteen ON patients were classified as four groups based on their clinical and MRI characteristics, as well as serum and CSF testing results: [1] definite PON, 6 cases (11 eyes); [2] possible PON, 3 case (5 eyes); [3] meningeal carcinomatosis-associated optic neuropathy (MCON), 4 cases (6 eyes); [4] infiltrative optic neuropathy (ION), 2 cases (2 eyes). Malignant cells were found under microscope in CSF samples from MCON and ION patients, contrast to no malignant cells in CSF samples from PON cases. All 14 ON patients with malignant tumors showed negative results in serum tests for pathogens and autoantibodies. Serum paraneoplastic antibodies were tested in PON patients, anti- CV2, anti-Yo, and anti- amphiphysin were detected positive in 2, 1, and 1 case, respectively, in definite PON group, whereas no serum paraneoplastic antibody detected in possible PON group. Two unknown serum antineuronal antibodies (an anti- Purkinje cell antibody and an anti-granular cell antibody) were detected using monkey cerebellar tissue-based assay in 2 of 5 PON patients with negative paraneoplastic antibody test results.

CONCLUSIONS

Serum and CSF tests are of great importance in differentiating different subtypes of ON with malignant tumors. Current diagnosis of PON still depends on combination of clinical and MRI manifestations, as well as serum and CSF tests. Tissue-based assay may help to detect new biomarkers for ON etiology and diagnosis.