Unsuspected recurrent pituitary adenoma presenting as an orbital mass.

PURPOSE Orbital invasion of pituitary tumors is rare and usually accompanied by optic nerve head pallor and visual loss. We describe a case of unilateral massive orbital invasion by a recurrent pituitary tumor with preserved visual acuity and normal optic nerve appearance. METHODS Case report. RESULTS Progressive proptosis developed 15 years after transphenoidal removal of a pituitary tumor. Based on the radiological appearance and the clinical history, the patient was suspected to have a sphenoid wing meningioma secondary to previous radiation treatment. A combined neurosurgical and orbital approach was used to remove the intraorbital mass, which extended from the cranial cavity through the superior orbital fissure and the optic canal. Histopathologic examination demonstrated a recurrent nonsecreting pituitary adenoma. CONCLUSIONS Orbital extension of a recurrent pituitary adenoma should be considered in the differential diagnosis of progressive proptosis even in the absence of significant optic neuropathy.