TY - JOUR T1 - Retinoblastoma and optic nerve enhancement on MRI: not always extraocular tumour extension JF - British Journal of Ophthalmology JO - Br J Ophthalmol SP - 800 LP - 801 DO - 10.1136/bjo.2005.089383 VL - 90 IS - 6 AU - P de Graaf AU - A C Moll AU - S M Imhof AU - P van der Valk AU - J A Castelijns Y1 - 2006/06/01 UR - http://bjo.bmj.com/content/90/6/800.abstract N2 - Neoadjuvant chemotherapy is useful in the management of extensive forms of retinoblastoma with radiologically detectable optic nerve invasion at diagnosis.1 Magnetic resonance imaging (MRI) can detect various degrees of optic nerve invasion as enhancement extending from an intraocular tumour into the optic nerve. However, pretreatment false positive MRI findings based on inflammation occur occasionally.2 We describe a case of unilateral retinoblastoma and false positive MRI findings of extensive optic nerve involvement. A 3 year old girl presented with retinoblastoma of the right eye. Ophthalmic examination revealed a large exophytic growing tumour, a shallow anterior chamber, rubeosis iridis, and an elevated intraocular pressure. T2WI showed a hypointense subretinal tumour mass with similar signal intensity (SI) compared to both optic nerves (fig 1A). No delineation of the ipsilateral optic nerve with surrounding cerebrospinal fluid was possible. On additional short tau inversion recovery (STIR) MRI, the optic nerve showed an increased SI from the postlaminar part to the orbital apex. Contrast enhanced T1WI showed enhancement of the tumour mass (tumour volume 2.1 cm3). Thickening and marked enhancement … ER -