Purpose: To describe a type IIIa frontal mucocele in a case of diffuse nasal polyposis. To discuss the clinical presentation, diagnostic and treatment modalities. Study Design: A case report including radiological, histopathological analysis and review of literature. Methods: A case report from a tertiary care centre. Histopathologic and radiological details are reviewed. Results: This case report presents a 59-year-old male who came to us with fronal headaches and nose blocks of 6 months’ duration. Clinical examination revealed bilateral nasal polyposis. Plain CT scan of paranasal sinuses revealed a circumscribed lesion with erosion of inner table of left frontal sinus amidst pan sinus haziness. We addressed the condition by combined FESS with eyebrow incision frontal craniotomy. Histopathological examination revealed a mucocele. Conclusion: In combined approach, eyebrow incision minimal frontal craniotomy remains the optimal option for visualisation of entire sinus, especially in laterally placed frontal mucoceles; while FESS helps in maintaining physiological drainage and proper follow-up.