CASE REPORT Partial visual recovery from radiation-induced optic neuropathy after hyperbaric oxygen therapy in a patient with Cushing disease Mara Boschetti 1 , Massimo De Lucchi 2 , Massimo Giusti 1 , Claudio Spena 2 , Guido Corallo 3 , Umberto Goglia 1 , Enrica Ceresola 1 , Eugenia Resmini 1 , Lara Vera 1 , Francesco Minuto 1 and Diego Ferone 1 1 Department of Endocrinological and Metabolic Sciences and Center of Excellence for Biomedical Research, 2 Department of Anesthesiology, Unit of Hyperbaric Therapy and 3 Institute of Ophthalmology, Universityof Genoa and San Martino Hospital, Viale Benedetto XV, 6, I-16132, Genoa, Italy (Correspondence should be addressed to D Ferone; Email: ferone@unige.it) Abstract Here we describe the case of a 41-year-old woman with a history of Cushing disease who had previously undergone unsuccessful neurosurgery, followed by stereotactic radiosurgery. More than 4 years after this treatment, she presented severe visual impairment, which started in the left eye and was documented by neuro-ophthalmic evaluation. Radiological assessment by contrast-enhanced magnetic resonance (MR) imaging initially suggested the diagnosis of glioma of the optic nerve and the patient started corticosteroid treatment (first with prednisone, 80 mg/day, followed by dexamethasone, 8mg/day). Despite the therapy, vision in the left eye rapidly worsened until light was no longer perceptible; similar symptoms and signs also developed in the right eye, evolving to complete temporal hemianopsia. The clinical evidence was confirmed by the rapid progression of the MR picture, which showed homogeneous enhancement of the chiasm and optic nerves. On the basis of these findings, the original diagnosis of glioma was excluded, and radiation-induced optic neuropathy was diagnosed. As corticosteroids had proved inefficacious, hyperbaric oxygen (HBO) therapy was promptly instituted and vision steadily started to improve. This improvement was documented and confirmed by the progressive recovery of the visual field in the right eye and the changes in the sequential follow-up MR scanning. Optic neuropathy is an infrequent but dramatic complication of radiation therapy. Symptoms develop, on average, 12 months after treatment, and the onset may be acute and characterized by the progressive loss of vision in one or both eyes. HBO has already been used to treat this complication, but its efficacy is still controversial. Here, in addition to describing this particular case, which presented a significantly delayed radiation injury of the optic pathways, we provide a brief literature review and discuss some important points. European Journal of Endocrinology 154 813–818 Introduction For many years, radiotherapy has been used to treat pituitary adenomas after failure of surgery. Despite a maximal 45–55 Gy dose with optimal standard daily fractionation of 1.8–2 Gy, a few serious complications (i.e. temporal brain necrosis and optic neuropathy) have occurred; consequently, endocrinologists and neurosur- geons have tended to limit the use of this approach (1). However, the last decade has seen important advances in radiotherapy technology which combine precise tumor localization with accurately targeted delivery of radiation. This technique of high-precision conformal radiotherapy, described as stereotactic radiotherapy or radiosurgery, uses modern linear accelerators available in most radiation departments, and has renewed the role of radiation therapy in pituitary adenomas (1,2). Characterized by abrupt and permanent visual loss, optic neuropathy is a recognized but infrequent dramatic complication of radiation therapy. Symptoms develop, on average, 12 months after conventional treatment; the onset may be acute and is followed by the progressive loss of vision in one or both eyes, to the point of total blindness (3,4). This complication generally occurs after cumulative doses of radiation exceeding 50 Gy, or single doses greater than 10 Gy delivered to the visual apparatus. Visual loss may result from lesions of the disc, the retrobulbar segment of the optic nerve, optic chiasm, or even the retrogeniculate pathways (3, 4). The second eye may develop abnormalities and clinical manifestations of optic neuropathy from days to months after the diagnosis in the first eye involved. Various treatments, including corticosteroids, have generally failed to reverse or even halt the loss of vision due to radiation injury of visual pathways (4). Hyperbaric oxygen (HBO) therapy has also been used to treat this complication, but its efficacy is still controversial. We report the case of a patient who European Journal of Endocrinology (2006) 154 813–818 ISSN 0804-4643 q 2006 Society of the European Journal of Endocrinology DOI: 10.1530/eje.1.02161 Online version via www.eje-online.org