Mucocele of the Sphenoid, Ethmoid and Frontal Sinuses Presenting with Proptosis, Visual Impairment and Diplopia

Author PY analyzed the case and searched literature, wrote the article and statistical analysis. ABSTRACT Mucocele of the paranasal sinus is accumulation of the mucoid secretion within the sinus caused by obstruction of the sinus ostium. We report a case of paranasal sinus mucocele presented with proptosis in right eye, diplopia, visual impairment and headache. Magnetic resonance imaging(MRI) revealed a polyp in right anterior ethmoid sinus and nasal cavity resulted in mucocele of the sphenoid, ethmoid and right frontal sinuses.


INTRODUCTION
Mucocele is a benign condition, however it has tendency to expand and erodes the bony wall and may extend into the adjacent orbit or into the anterior cranial fossa. It is occasionally presents with proptosis, diplopia and visual impairment. It is rarely presents with cerebral abscess or meningitis. It is more common in frontal sinuses, less common in ethmoid sinuses and rare in sphenoid sinus, which constitutes less than 2% of all paranasal sinuses mucocele [1]. Early diagnosis and management of mucocele is important to prevent Case Study morbidity and potential mortality. MRI has important role to evaluate the intraorbital and intracranial extent.

CASE REPORT
A 24-year old female presented with a history of visual impairment since 15 days, proptosis in right eye, diplopia and headache since 4 months. CT scan of the paranasal sinuses was done which revealed cyst like expansile lesion involving sphenoid, bilateral ethmoid and right frontal sinuses Fig. 1. There was a polyp in the right anterior ethmoid sinus and nasal cavity, which was obstructing the sinus ostium. There was bony expansion of the involved sinuses. Erosion of the medial wall of both the orbits was seen. There was 5.5mm forward proptosis seen in the right eye. Marked deviated nasal septum wasseen towards left side.

DISCUSSION
Langenbeck first described mucocele of the paranasal sinuses in 1820 under the name of hydatides. Rollet suggested the name mucocele [2]. Fronto-ethmoidal mucoceles may present headache, proptosis(83%) and diplopia(45%) [3]. Clinical features of mucocele depends upon its anatomical site, it may be asymptomatic or can give visual impairment [3]. Mucocele is chronic, epithelial lined mucosal retention lesion due to obstruction of the sinus ostium. The obstruction may be due to congenital anomalies, trauma, neoplasm, infection, allergy or surgical procedure [4]. Continued secretion and accumulation of mucus causes increasing pressure, expansion and bony erosion of the sinus allow to expand into the orbit, intracranial, adjacent sinuses and nasal cavity [5,6]. Approximately 60-89% occurs in the frontal sinus, followed by 8-30% in the ethmoid sinuses, and less than 5% in the maxillary sinus. Sphenoid sinus mucoceles are rare (less than 2 %) [1]. Males and females are equally affected. Diagnosis of the mucocele is based on history, examination and radiological findings. CT findings of mucocele are homogenous non-enhancing expansile lesion in sinus with bone erosion and displacement of the adjacent structure. Magnetic resonance imaging findings are variable which depends upon the amount of fluid content, proteinaceous component or hemorrhage [7]. They are usually hypo or isointense on T1WI and hyperintense on T2WI. Differential diagnosis of mucocele is paranasal sinus carcinoma, Aspergillus infection or chronic infection [5]. Complications of mucocele are epidural abscess, meningitis, subdural empyema, brain abscess and visual loss [5]. When it is secondarily infected, it is called as pyocele. The treatment of mucoceles is surgical. In our case a large polyp in the right anterior ethmoid sinus and nasal cavity was obstructing the sinus ostium and was resulted in the mucocele of the right fronto-ethmoidal and sphenoid sinuses. There was frontal mucocele which was causing pressure on the anterior aspect of right frontal lobe. In our case there was mucocele in right frontal, ethmoid and sphenoid sinuses simultaneously. Surgical goal is to drain the mucocele and ventilate the sinus involved along with eradication of the mucocele with minimal morbidity and prevention of recurrences [8,9].

CONCLUSION
Mucocele of the paranasal sinus is an important cause for proptosis, diplopia and visual impairment. Early diagnosis and timely management is of paramount importance to prevent the intracranial and intraorbital extension and its complications. MRI is the best modality to evaluate the extent of the mucocele. Contrast enhanced MRI is useful in differentiating mucocele from Sino nasal tumours.

CONSENT
Author declares that 'written informed consent was obtained from the patient for publication of this case report and accompanying images.

ETHICAL APPROVAL
Approval from the ethical committee of the hospital was obtained.