Background and Clinical Significance: Frontal sinus disease remains one of the most challenging conditions in rhinology due to its complex and variable anatomy and high tendency toward postoperative stenosis. Paranasal sinus mucoceles are uncommon, delayed complications following functional endoscopic sinus surgery (FESS), most often involving the frontal or anterior ethmoidal sinuses. They may arise from obstruction or scarring of natural drainage pathways, producing recurrent sinusitis or headache; Case Presentation: A 21-year-old male presented with persistent left-sided frontal headache and nasal obstruction after two previous FESS procedures. Radiologically, CT and MRI demonstrated chronic left-sided sinonasal inflammatory disease and two frontal-ethmoidal mucoceles. Revision endoscopic sinus surgery was performed with an image-guided (neuronavigation-assisted) technique, including Draf IIb frontal sinusotomy, mucocele marsupialization, and corrective septoplasty. The postoperative course was uneventful with rapid clinical improvement; Conclusions: Double postoperative mucoceles following ESS are rare. Neuronavigation-assisted revision surgery can be used for effective management in scarred, anatomically distorted sinus regions. However, this single case cannot establish superiority over conventional endoscopic guidance or demonstrate an effect on safety, efficacy, or recurrence.