A 35-year-old woman developed painful proptosis of the left eye over a period of 3 weeks. Orbital computed tomography and magnetic resonance imaging revealed a well-circumscribed superior orbital tumor with variable density. The mass was removed entirely by way of a superior orbitotomy. Histopathologically, it was found to be a neurofibroma. The patient had no clinical findings of neurofibromatosis. The presence of extensive myxomatous degeneration and the dense collection of collagen bundles in the tumor are correlated with the unusual computed tomography and magnetic resonance imaging features.