The main differentials for the lesions invading and destroying the ethmoidal sinuses on the left are sinonasal carcinoma and inverted papilloma.  

The case was histologically proven to be an ethmoidal inverted papilloma, which shows to extend into the left frontoethmoidal recess, with fluid opacification of the left frontal sinus. No overt invasion into the frontal sinus, although its inferior wall is deficient. No evidence of intracranial invasion.