Figure 5. Case 6. (A,B) Left fronto-ethmoidal mucocele with obstructed left frontal drainage and associated with left unilateral proptosis (low signal intensity in T1 and high signal in T2); it is significantly encroaching upon the left orbital cavity, displacing and compressing left orbital structures without gross invasion; (C,D) CT scan showing left fronto-ethmoidal lobulated cystic lesion measures about 5 x 4 x 2.8 cm, with extending mainly to left retrobulbar space with associated left proptosis; there is associated expansion/remodelling and erosions of the left lamina papyracea and medial superior orbital wall.