Lumbosacral plexiform neurofibroma: a rare case in an adult without neurofibromatosis type I

Miniature Palpebral Plexiform Neurofibroma in Neurofibromatosis Type 2

A 27-year-old woman with well-documented neurofibromatosis 2 developed a soft, painless, nodular lesion on the skin surface of the left upper eyelid over 2 years. Following excision, histopathology revealed a plexiform neurofibroma with intradermal nodules comprised of benign round and spindle cells that reacted diffusely with immunohistochemical stains SOX-10 and S100. A subset showed focal reactivity for neurofilament and CD34. A perineurium surrounded each nodule with cells staining positively for markers EMA (epithelial membrane antigen) and GLUT1 (glucose transporter 1). Plexiform neurofibromas are rare tumors that occur in 5%-15% of patients with neurofibromatosis 1. Cutaneous abnormalities in neurofibromatosis 2 have not been widely studied although reports have described schwannomas, plexiform schwannomas, and occasional neurofibromas. Plexiform neurofibromas in neurofibromatosis 2 have rarely been illustrated and the current case represents a unique bona fide eyelid example to date.