Foot Drop as an Unusual Presentation of Plexiform Neurofibroma: A Case Report of an Otherwise Healthy Female
Keywords:foot drop, plexopathy, plexiform neurofibroma, electrodiagnosis, rehabilitation
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
Carolus AE, Becker M, Cuny J, Smektala R, Schmieder K, Brenke C. The interdisciplinary management of foot drop. Dtsch Arztebl Int. 2019;116:347-54.
Chang LR, Shieh SJ. Neurofibroma derived from the deep peroneal nerve: a case report. Kaohsiung J Med Sci. 2006;22:290-6.
Lin V, Daniel S, Forte V. Is a plexiform neurofibroma pathognomonic of neurofibromatosis type I? Laryngoscope. 2004;114:1410-4.
Atkins NK, Stensby JD, Gaballah AH. Lumbosacral plexiform neurofibroma: a rare case in an adult without neurofibromatosis type I. Skeletal Radiol. 2020;49:321-30.
Nagel A, Greenebaum E, Singson RD, Rosenwasser MP, McCann PD. Foot drop in a long-distance runner. An unusual presentation of neurofibromatosis. Orthop Rev. 1994;23:526-30.
Carpenter B. Neurofibroma of the anterior aeg: a case report. FAOJ. 2012;5. doi: 10.3827/faoj.2012.0506.0002
Hirbe AC, Gutmann DH. Neurofibromatosis type 1: a multidisciplinary approach to care. Lancet Neurol. 2014;13:834-43.
Tadini G, Milani D, Menni F, Pezzani L, Sabatini C, Esposito S. Is it time to change the neurofibromatosis 1 diagnostic criteria? Eur J Intern Med. 2014;25:506-10.
Ferner RE. Neurofibromatosis 1 and neurofibromatosis 2: a twenty first century perspective. Lancet Neurol. 2007;6:340-51.