Orbital Neurofibroma Presenting with a Negative Hounsfield Unit on Computerized Tomography

Abstract

Purpose: To report a case of diffuse orbital neurofibroma which displayed an unusual computed tomography (CT) feature. Methods: Results of ocular examination, orbital CT examination and pathological findings in a patient with a space-occupying orbital lesion are presented. Results: Orbital CT evaluation of a male patient, aged one and a half years old, revealed a right orbital lesion with a strongly negative value in Hounsfield units. The preoperative diagnosis was a dermoid cyst. An anterior orbitotomy was performed, and the surgical specimen demonstrated a typical plexiform neurofibroma with routine hematoxylin and eosin staining and immunohistochemical studies. Conclusions: Plexiform orbital neurofibromas may demonstrate a negative Hounsfield value on CT examination.

KEYWORDS:

• Computed tomography
• neurofibroma
• orbit
• diagnosis
• imaging