Mucopyocele: An Entity Infrequently Reported as a Complication of Functional Endoscopic Sinus Surgery

Abstract

Paranasal sinus mucocele or mucopyocele development after functional endoscopic sinus surgery is an infrequent phenomenon. The risk of mucocele development after endoscopic surgery for nasal polyposis or for chronic rhinosinusitis with nasal polyposis increases with greater preoperative Lund-Mackay score, with suboptimal post-operative management and with infrequent follow up post-surgery. We are reporting a case of bilateral fronto-ethmoidal mucocele developing secondary to FESS, its management and a brief literature review.

Introduction

Functional endoscopic sinus surgery (FESS) has gained popularity for diagnosis and treatment of patients with paranasal sinus diseases. Its outcome has improved because of advanced endoscopic techniques, intraoperative navigation, and improved surgical training. Despite its success 1% of patients may develop complications.

Patients with chronic rhinosinusitis with nasal polyps have more severe symptoms, higher CT score, making them prone for less improvement post-surgery. It also increases the risk of revision surgery and mucopyocele formation.

Mucopyocele formation secondary to FESS has not been frequently reported in literature. We are reporting one such case along with a brief and relevant literature review.

Case Report

A thirty-seven year old female presented to our outpatient department with complaints of fever, headache, and left periorbital swelling along with proptosis for 5 days. It was associated with painful eye movements and nasal blockage and nasal discharge. She had undergone a functional endoscopic sinus surgery for bilateral nasal polyposis one year back with Lund-Mackay score of 24 (Fig. 1) During her postoperative follow up synechiae (left nasal cavity) and few early polyps (right nasal cavity) were noted. Patient was advised conservative management and regular follow up but patient was unable to follow up regularly.

Fig. 1.

Preoperative NCCT of PNS. a, Multiple Polypoidal soft tissue masses almost completely filling Paranasal sinuses and Nasal cavity (a, arrows). Hyperdense contents are seen in the centre of soft tissue in maxillary and ethmoid sinuses (a, arrowhead), could be due to superimposed fungal sinusitis or hyperdense secretions. b Bone windows; diffuse thinning and remodelling of Ethmoid walls (b, arrows) seen in sinonasal polyposis

On examination of the left eye, there was left periorbital swelling with lid edema and proptosis with movement restricted in all gazes. Left eyeball was shifted down and out. (Fig. 2) The vision was diminished (6/12), pupillary reaction, and accommodation was normal. On endoscopic examination on the left side a smooth bulge from the lateral wall was seen and on the right side synechiae along with polyps were seen between the maxillary meatus and lateral wall. MRI was done to evaluate paranasal sinuses and orbits (Fig. 2). T2 weighted images revealed hyperintense bilateral fronto-ethmoidal mucoceles. Expansile bony remodeling of frontoethmoidal sinuses caused severe compression of extraconal and intraconal compartments and orbital muscles of left orbit resulting in left proptosis. Both the optic nerves were normal in signal intensity. Mild compression of right orbit was also seen. However, there was no evidence of orbital invasion or cellulitis. Clinical history, examination and radiological features suggested a probable diagnosis of mucocele. Under monitored anesthesia control, the collection was drained through trans nasal endoscopic approach. Around 10–15 mL thick, yellow secretions were drained taking us to the diagnosis of mucopyocele. It was well marsupalized into the nasal cavity. Synechiae were released and mucosal polyps were also removed. Patient is doing well at nine months follow up with no new synechiae or polyp formation and no evidence of recurrence of mucopyocele.

Fig. 2.

MRI of Paranasal sinuses after 16 months of FESS for Sinonasal Polyposis. a Coronal T2W MRI shows Bilateral Fronto-Ethmoidal Mucocele with severe bony expansion and remodelling. It is compressing Extraconal space of Both orbits (a, arrows) resulting in Left Proptosis (a, curved white arrow). Mucocele of right bulla ethmoidalis is compressing right osteomeatal complex resulting in right maxillary sinusitis (a, white thick arrow). b Anterior ethmoid mucoceles (b, arrows) compressing right spheno-ehtmoidal recess resulting in sphenoid and Posterior ethmoid sinusitis (b, arrowheads)

Discussion

FESS, like any other surgical procedure may be associated with some immediate, short term and long-term complications. Major intraoperative and short-term complications include CSF leak, orbital injuries and hemorrhage and meningitis [1] Long term complications and sequelae include empty nose syndrome, scarring, synechiae and paranasal sinus mucocele or mucopyocele.

Paranasal sinus mucopyocele is epithelial lined cystic lesion filled with muco-pus often associated with bony expansion due to obstruction of sinus drainage. The exact cause for development of mucopyocele is not known, but it may be secondary to obstruction of sinus ostium because of inflammation like in nasal polyposis, CRS, trauma or repeated surgeries [2]. The expansion of mucopyocele is by slow bone erosion and remodelling causing it to extend into the orbit, nasal cavity or cranial cavity. The rate of expansion may be increased by inflammatory mediators like prostaglandin, interleukin and tumor necrosis factor which all can help to expand besides pressure changes [3].

The clinical presentation depends on location and direction of expansion and presence of infection, with the frontal sinus being affected the most followed by ethmoid. Frontal and anterior ethmoid mucoceles presents with periorbital swelling, proptosis, reduced ocular mobility and frontal headaches whereas posterior ethmoid and sphenoid mucoceles present with visual disturbances, generalized headaches, diplopia and orbital displacement [4]. The diagnosis is usually made by history, examination, and radiologic findings. Imaging is inevitable in diagnosis and assessment of sinonasal mucoceles. CT is often the cross-sectional imaging of choice in evaluation of inflammatory paranasal sinus diseases, including mucopyoceles. Mucopyoceles appear as hypodense to isodense, expansile cystic masses completely filling the corresponding sinus with no residual air (Fig. 2) CT is also an excellent modality to delineate bony anatomy of sinuses and drainage pathways. On the other hand, MRI is the best cross-sectional imaging to evaluate orbital and intracranial extension. Signal intensity of mucopyocele on T1W and T2W MR imaging varies with its contents and duration. Recent mucopyoceles have less protein and more water content and appear hyperintense on T2W and hypointense on T1W imaging. While chronic mucoceles may appear hypointense on T2W and hyperintense on T1W imaging due to high protein contents [5]. On postcontrast MR imaging it shows smooth peripheral enhancement contrary to tumors which show heterogenous global enhancement. The treatment of choice is surgical drainage and marsupialization of the affected sinuses [3]. For frontal sinus mucopyoceles, Draf- IIa or IIb procedure is recommended to prevent recurrence.

In nasal polyposis, the mucosa remains inflammatory causing mucociliary dysfunction which leads to excess mucin leading to highly viscoelastic mucus and mucostasis. This persistent inflammation affects the post surgical follow up with greater risk of mucopyocele formation, and making it prone for recurrence, and is also a cause for surgical failure and revision FESS. A higher Lund-Mackay score is corelated with lower mucociliary clearance, leading to more sinus opacification and increasing the risk of mucocele formation.

The frontoethmoidal area is more prone for mucpyoocele as it is narrow with more mucosal contacts. Preoperative oral steroids reduce the polyp size thereby increasing the intraoperative visibility. Improved visibility helps in better ostium opening and decreased collateral mucosal damage; ultimately decreasing the chances of mucopyocele formation in long term [6].

The post operative management aims to prevent post operative infection, synechiae formation which can lead to obstruction and recurrence requiring revision FESS. To reduce the probability of synechiae formation, careful and atraumatic maneuvering of endoscopes and instruments inside the nasal cavity is of paramount importance. Need for regular periodical follow up must be emphasized to the patient in pre-operative period itself. Careful assessment of the nasal cavity and debridement of the dead tissue (if any) is performed at each post-operative follow up. Generally, first follow up at two weeks and then every four weeks till the cavity is well healed, is advised and recommended [7].

Conclusion

Mucopyocele formation is a rare post operative complication of FESS. Patients undergoing FESS must be counselled preoperatively regarding post operative management, and the need of regular follow up in order to reduce the complications and for better surgical outcome. An increased watchfulness is desirable in patients with high preoperative Lund-Mackay score as they are prone for complication [6]. The best way forward to minimize complications is by emphasizing on meticulous atraumatic handling of nasal mucosa during surgery and regular post-operative follow up in this group of patients.

Funding

The authors did not receive support from any organization for the submitted work.

Availability of Data and Material

Already available data has been reviewed, tabulated and analysed. Consent for the same has been obtained from the patient.

Compliance with Ethical Standards

Conflict of interest

The authors have no conflicts of interest to declare that are relevant to the content of this article.

Ethics Approval

This is a case report (observational study). The AIIMS Bhopal Human Ethics Committee has confirmed that no ethics approval is required.

Consent to Participate

Informed consent was obtained from the participant included in the study.

Consent for Publication

The authors affirm that human research participants provided informed consent for publication of the images in Figure(s) 1a, 1b, 2a and 2b. The participant has consented to the submission of the case report to the journal.