Spontaneous Resolution of Diplopia Related to a Frontal Sinus Mucocele

Clinical Correspondence Section Editors: Robert Avery, DO Karl C. Golnik, MD Caroline Froment, MD, PhD An-Guor Wang, MD Spontaneous Resolution of Diplopia Related to a Frontal Sinus Mucocele Jim S. Xie, BHSc, Jonathan A. Micieli, MD A notable consequence of the COVID-19 pandemic was reduced availability of operating room time for nonurgent procedures. We report a unique case where COVID19–related operating room restrictions permitted observation of the natural history of diplopia associated with frontal sinus mucocele. A 71-year-old man was referred for new onset diplopia. He had a medical history of hypertension and benign prostatic hyperplasia, and his medications included telmisartan and tamsulosin. He also had a history of chronic sinusitis and inverted papilloma of the nasal cavity that was removed 5 years before presentation without complication. He developed new onset binocular diplopia 2 months before presentation. Objects were separated vertically, and this was worse when he looked upward. He was initially believed to have a third nerve palsy and was referred for neuro-ophthalmic assessment. Examination revealed a visual acuity of 20/20 (right) and 20/ 20 (left), normal confrontational visual fields, and equally sized pupils without a relative afferent pupillary defect. External examination revealed a limitation of elevation in his left eye and a left hypotropia in primary position (Fig. 1A). Cranial nerve function was otherwise normal. The limitation of eleva- tion in the left eye raised concern for a left orbital process, and a computed tomography (CT) scan of the orbits was obtained to better identify the lesion. CT showed expansion of an opacified left frontal air cell, which projected into the superior and medial aspects of the left orbit, with partial dehiscence of the orbital roof and adjacent upper lamina papyracea (Fig. 1B). Compression deformity and displacement of the superior levator complex and superior oblique muscle were observed along with mild inferior displacement and deformity of the medial rectus muscle. The diagnosis was most consistent with a frontal sinus mucocele. He was referred to Otolaryngology-Head and Neck Surgery. However, owing to COVID-19–related limitations in operating room availability, the patient was considered lower priority and surgery was not scheduled. After 3 months, the patient reported that his double vision resolved. Repeat examination at that time revealed full ocular ductions, and he was orthophoric in the primary position (Fig. 2A). Repeat CT orbits showed an interval decrease in size of the left frontal mucocele (Fig. 2B). Frontal sinus mucoceles are pseudocystic, epitheliumlined accumulations of mucous discharge caused by obstructed drainage through sinus ostia. These lesions have a FIG. 1. A. External photographs at presentation demonstrated a limitation of elevation in the left eye. B. Computed tomography of the orbits at presentation showed a left frontal sinus mucocele invading the left orbit. Michael G. DeGroote School of Medicine (JSX), McMaster University, Hamilton, Ontario, Canada; Department of Ophthalmology and Vision Sciences (JAM), University of Toronto, Toronto, Ontario, Canada; Division of Neurology (JAM), Department of Medicine, University of Toronto, Toronto, Ontario, Canada; and Kensington Vision and Research Centre (JAM), Toronto, Ontario, Canada. The authors report no conflicts of interest. Address correspondence to Jonathan A. Micieli, MD, Kensington Vision and Research Centre, 340 College Street, Suite 501, Toronto, ON, Canada M5T 3A9; E-mail: [e-mail] e256 natural tendency to expand because of continuous mucous production from the internal epithelium and fibroblastmediated bony erosion of the surrounding sinus walls (1). Because the frontal sinus has close anatomical relations with the brain and orbits, mucoceles in this location are prone to intraorbital and intracranial invasion. The clinical manifestations of frontal sinus mucoceles primarily arise from the mass effect on the adjacent tissue. Xie and Micieli: J Neuro-Ophthalmol 2023; 43: e256-e257 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence FIG. 2. A. External photographs at the final follow-up showed full ocular ductions in both eyes. B. Computed tomography of the orbits at the final follow-up showed a left frontal sinus mucocele significantly reduced in size. Patients with frontal sinus mucoceles commonly experience bifrontal headache with or without facial asymmetry and swelling (1). Intraorbital extension most frequently causes proptosis (83%) and diplopia (45%) but may also cause symptoms such as eye pain, decreased visual acuity, and restricted ocular motility (1). Although frontal sinus mucoceles are considered benign growths, invasion of the brain and orbits may incur significant morbidity and even mortality if treatment is delayed. Intraorbital extension may cause prolonged compressive or ischemic compromise of the optic nerve, leading to permanent visual loss and poor visual prognosis. To decrease the risk of complications and recurrence, it is important that frontal sinus mucoceles are diagnosed and treated in a timely manner. The mainstay of treatment is surgery, of which the primary aims are to eliminate mucoceles through excision or drainage and to restore sinus ventilation and outflow (1). Advances in surgical technology and understanding of disease course have propelled a shift from traditional external approaches focused on ablation to minimally invasive endoscopic procedures that prioritize mucocele drainage (1). In this unique case COVID-19–related restrictions allowed us to observe the natural history of binocular diplopia secondary to frontal sinus mucocele. Spontaneous resolution of visual symptoms associated with nonoperated paranasal sinus mucoceles has rarely been reported in the literature. Palmer-Hall and Anderson (1997) reported one of the earliest cases of spontaneously resolving mucoceles, describing a patient with acute vision loss associated with polypoid disease and frontoethmoidal sinus mucoceles whose vision improved over 2 weeks without surgical intervention (2). A more recent case report discussed a patient with sudden nasal hemianopsia who refused treatment for an ethmoid sinus mucocele. Five years after initial presentation, her visual symptoms remained unchanged but no lesions were detected on repeat CT (3). A similar watchful waiting approach was taken by Hansen et al (2018) in 3 patients who demonstrated MRI evidence of frontal sinus mucoceles during the postoperative follow-up of frontal sinus obliteration. No measurable progression could be seen in Xie and Micieli: J Neuro-Ophthalmol 2023; 43: e256-e257 2 of these patients during 3–4 years of follow-up, but lesion expansion was observed in the third patient over 6 years (4). In addition to frontoethmoidal mucoceles, spontaneous resolution has also been reported in nasal mucoceles. Smith et al (2015) discussed 2 patients who developed nasal mucoceles after transsphenoidal surgery for Cushing disease. Regular nasal hygiene and saline spray without further intervention resolved mucoceles in both patients (5). In conclusion, we report a patient with an intraorbitally extending frontal sinus mucocele whose ophthalmic symptoms resolved spontaneously. This case, in combination with similar case reports in the literature, suggests that conservative management can be considered in certain patients with frontal or paranasal sinus mucoceles, even if these lesions extend into the orbit and produce ophthalmological complications. A short period of watchful waiting is reasonable as long as the optic nerve is not compromised. STATEMENT OF AUTHORSHIP Conception and design: J. A. Micieli; Acquisition of data: J. S. Xie, J. A. Micieli; Analysis and interpretation of data: J. S. Xie, J. A. Micieli. Drafting the manuscript: J. S. Xie, J. A. Micieli; Revising it for intellectual content: J. S. Xie, J. A. Micieli. Final approval of the completed manuscript: J. S. Xie, J. A. Micieli. REFERENCES 1. Aggarwal SK, Bhavana K, Keshri A, Kumar R, Srivastava A. Frontal sinus mucocele with orbital complications: management by varied surgical approaches. Asian J Neurosurg. 2012;7:135– 140. 2. Palmer-Hall AM, Anderson SF. Paraocular sinus mucoceles. J Am Optom Assoc. 1997;68:725–733. 3. Morganti L, Evangelista L, Guimaraes R, Crosara P. Sudden hemianopsia secondary to ethmoid sinus mucocele. Int Arch Otorhinolaryngol. 2014;18:319–321. 4. Hansen FS, van der Poel NA, Freling NJM, Fokkens WJ. Mucocele formation after frontal sinus obliteration. Rhinology. 2018;56:106–110. 5. Smith TR, Hulou MM, Huang KT, Nery B, de Moura SM, Cote DJ, Laws ER. Complications after transsphenoidal surgery for patients with Cushing’s disease and silent corticotroph adenomas. Neurosurg Focus. 2015;38:E12. e257 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.