We present the clinical, radiological, and histopathological findings from a case of unilateral inflammatory mass of the right orbit, originating in the ipsilateral paranasal sinuses. A connection between inflammatory tumors of the orbit and paranasal sinusitis has been suspected for many years. This case shows a definite association between chronic paranasal sinusitis, orbital cellulitis, subperiosteal abscess, and formation of an inflammatory orbital tumor. Early diagnosis combined with appropriate therapeutic measures is essential in order to prevent adverse consequences, which can include severe visual loss.