Painful vertical diplopia as a presentation of a pituitary mass

BACKGROUND: Pituitary tumours may present with a variety of neurological and endocrinological signs and symptoms. It is very rare however for them to present with sudden onset painful diplopia. The current literature and possible mechanisms for this are discussed. CASE PRESENTATION: We describe a case of a pituitary mass which presented with sudden onset painful diplopia with an associated restricted pattern on Lees Chart testing. This led to an initial working diagnosis of orbital myositis. CONCLUSION: Awareness of different modes of presentation of pituitary lesions is important so that appropriate imaging may be requested and delay in diagnosis prevented.