Fascicular Sixth Nerve Palsy as a Presenting Sign of Metastatic Ovarian Carcinoma

The most common etiology of an isolated abducens nerve palsy in an older adult with vasculopathic risk factors is presumed microvascular ischemia. Because the diagnosis of microvascular ischemia in this setting would not alter patient management, there is debate as to whether further workup is warranted under these circumstances. In this report, we describe a fascicular sixth nerve palsy as the initial presenting sign of metastatic ovarian carcinoma, and we highlight the importance of considering additional workup in select cases of isolated abducens nerve palsies.

Photo and Video Essay Section Editors: Melissa W. Ko, MD Dean M. Cestari, MD Peter Quiros, MD Fascicular Sixth Nerve Palsy as a Presenting Sign of Metastatic Ovarian Carcinoma Niloufar Rohani, BBA, Peter Mortensen, MD, Andrew G. Lee, MD FIG. 1. Gaze positions show abduction deficit in right gaze. Abstract: The most common etiology of an isolated abducens nerve palsy in an older adult with vasculopathic risk factors is presumed microvascular ischemia. Because the diagnosis of microvascular ischemia in this setting would not alter patient management, there is debate as to whether further workup is warranted under these circumstances. In this report, we describe a fascicular sixth nerve palsy as the initial presenting sign of metastatic ovarian carcinoma, and we highlight the importance of considering additional workup in select cases of isolated abducens nerve palsies. Journal of Neuro-Ophthalmology 2021;41:e372–374 doi: 10.1097/WNO.0000000000001188 © 2021 by North American Neuro-Ophthalmology Society Baylor College of Medicine (NR, AGL), Houston, Texas; Department of Ophthalmology (PM, AGL), Blanton Eye Institute, Houston Methodist Hospital, Houston, Texas; The Houston Methodist Research Institute (AGL), Houston Methodist Hospital, Houston, Texas; Departments of Ophthalmology (AGL), Neurology, and Neurosurgery, Weill Cornell Medicine, New York, New York; and Department of Ophthalmology (AGL), University of Texas Medical Branch, Galveston, Texas. The authors report no conflicts of interest. Address correspondence to Andrew G. Lee, MD, Blanton Eye Institute, Houston Methodist Hospital, 6560 Fannin Street, Suite 450, Houston, TX 77030; E-mail: [e-mail] e372 A 67-year-old Caucasian woman presented with acute binocular diplopia. Past medical history was significant for ovarian carcinoma, basal cell carcinoma, hypertension, and hyperlipidemia. She had occasional mild subjective gait difficulty, but did not have any tinnitus, headaches, or vomiting. Two years before presentation, the patient was diagnosed with FIGO Stage IIIC ovarian cancer. Imaging at that time revealed bilateral ovarian masses and large volume ascites with carcinomatosis in the abdomen and pelvis. No distant metastases were identified. Pathologic biopsy was consistent with primary ovarian clear cell carcinoma. She received neoadjuvant carboplatin and paclitaxel, underwent a hysterectomy and bilateral salpingo-oophorectomy, and completed 3 rounds of adjuvant chemotherapy with dose-dense paclitaxel and carboplatin. Her past ocular history was significant for anatomical narrow angles, for which she underwent prophylactic laser peripheral iridotomy 1 month before presentation. She denied the use of tobacco, alcohol, and illicit drugs. She was allergic to heparin and lidocaine, and was not taking medications at the time of presentation. Her past surgical history, family history, and extensive review of systems were otherwise negative. On examination, her visual acuity was 20/40 in both eyes. Intraocular pressure measurements were 12 mm Hg both eyes. The pupils were symmetric and reactive to Rohani et al: J Neuro-Ophthalmol 2021; 41: e372-e374 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Photo and Video Essay FIG. 2. Brain MRI axial section T1 (left) with contrast and T2 (right) fluid attenuation inversion recovery (FLAIR) showing enhancing parenchymal mass in the right pons. light in both eyes without relative afferent pupillary defect. Visual fields were full to confrontation. Motility examination showed a 20-prism diopter esotropia (ET), which increased to 25–30 ET in right gaze with a -2 abduction deficit in the right eye. In left gaze, she was straight with full motility in the left eye (Fig. 1). Slitlamp exam showed evidence of laser peripheral iridotomy bilaterally and 2+ nuclear sclerotic cataracts bilaterally. A full dilated fundus exam was normal in both eyes. A full neurologic exam only revealed a cranial nerve (CN) VI palsy. Although her age and vasculopathic risk factors TABLE 1. Case Reports of Patients with an Underlying Disease who Presented Solely with an Isolated CN VI Palsy Reference Saffra et al, 20113 Movsas et al, 20004 Zahavi et al, 20135 Jain et al, 20176 Bet-Shlimon et al, 20177 Ahlawat et al, 20158 Singh et al, 20199 Jaben et al, 201910 Yevale et al, 201711 Disorders Whose First Manifestation was an Isolated CN VI Palsy Rapidly expanding ACTH positive silent pituitary adenoma Intracranial plasmacytoma and multiple myeloma Multiple myeloma Tuberculoma Multiple sclerosis in a patient with no prior history Polycythemia vera Neurosyphilis in AIDS patient Drug-induced isolated cranial nerve VI palsy from pembrolizumab Severe pre-eclampsia presenting as postpartum diplopia Rohani et al: J Neuro-Ophthalmol 2021; 41: e372-e374 were significant predictors for a presumed microvascular etiology of an isolated right CN VI palsy, her cancer history led to the decision to obtain imaging. Repeat abdominal imaging revealed a new left upper quadrant omental lesion, and biopsy confirmed metastatic carcinoma. Brain MRI with contrast revealed lesions in the left parietal lobe and a 1.8- · 1.6- · 1.4-cm mass with adjacent vasogenic edema in the right pontomedullary junction, which explained the CN VI dysfunction (Fig. 2). These findings were consistent with metastatic disease. She subsequently underwent external beam stereotactic radiotherapy targeting the brain metastases and received 5 cycles of gemcitabine, bevacizumab, and carboplatin followed by 2 cycles of doxorubicin. Follow-up imaging revealed significantly smaller brain metastases, and the patient’s diplopia had improved; however, she still required prisms. A neurologically isolated CN VI palsy is commonly due to an ischemic mononeuropathy especially in an older adult with vasculopathic risk factors. These isolated, ischemic CN VI palsies typically resolve spontaneously within a few months (1). Because neuroimaging would not alter the management of an isolated CN VI palsy secondary to microvascular ischemia, some authors have argued that it is unnecessary to perform neuroimaging. However, as seen in Table 1, isolated CN VI paresis has been reported previously as the presenting sign of more serious disorders. In addition, in a prospective, multicenter, observational case series of isolated ocular motor nerve palsies, 16.5% of patients with presumed microvascular ischemia actually had an identifiable etiology such as neoplasm or large vessel infarcts. Interestingly, over 60% of these patients also had one or more vasculopathic risk factors (2). We believe, and most neuro-ophthalmologists would agree, that a history of cancer is also a “nonisolated” finding in CN VI palsy and should be an indication for consideration for neuroimaging. In our case, a fascicular CN VI palsy was the sole presenting e373 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Photo and Video Essay sign of new metastatic ovarian cancer in the dorsal pons. To our knowledge, this is the first such case to be reported in the English language ophthalmic literature. STATEMENT OF AUTHORSHIP Category 1: a. Conception and design: N. Rohani and A. Lee; b. Acquisition of data: N. Rohani and A. Lee; c. Analysis and interpretation of data: N. Rohani and A. Lee. Category 2: a. Drafting the manuscript: N. Rohani; b. Revising it for intellectual content: N. Rohani. Category 3: a. Final approval of the completed manuscript: N. Rohani, A. Lee, and P. Mortensen. 4. 5. 6. 7. 8. REFERENCES 1. Volpe NJ, Lee AG. Do patients with neurologically isolated ocular motor cranial nerve palsies require prompt neuroimaging? J Neuroophthalmol 2014;34:301–305. 2. 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Rohani et al: J Neuro-Ophthalmol 2021; 41: e372-e374 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.