Foot Drop as an Unusual Presentation of Plexiform Neurofibroma: A Case Report of an Otherwise Healthy Female

Abstract

Objectives: To describe an unusual presentation of plexiform neurofibroma in an otherwise healthy female patient.

Study design: Case report.

Setting: Department of Rehabilitation Medicine, King Chulalongkorn Memorial Hospital, Bangkok.

Subjects: A 46-year-old otherwise healthy female presenting with right foot drop.

Methods: Not applicable.

Results: An electrodiagnostic study was performed by a physiatrist to determine the cause and evaluate the severity of the foot drop and to reveal any evidence of abnormalities extending to the sacral plexus. The evidence discovered lead to further investigation, including magnetic resonance imaging (MRI) of the plexus, which confirmed the diagnosis of plexiform neurofibroma. The patient had no skin lesions and no family history of neurofibroma. The tumor was removed and a biopsy confirmed an intraneural neurofibroma. A plastic ankle foot orthosis was prescribed to assist ankle dorsiflexion and improve walking. Six months after surgery, power of the involved muscles showed no significant improvement.

Conclusions: Foot drop in healthy individuals can result from plexiform neurofibroma even without a definitive diagnosis of neurofibromatosis type 1. Electrodiagnostic study should be the first step before undertaking further investigation, e.g., MRI. MRI is prescribed to confirm the diagnosis and location of the lesion.

Keywords: foot drop, plexopathy, plexiform neurofibroma, electrodiagnosis, rehabilitation