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Plexiform Neurofibroma

Plexiform neurofibroma is a subcutaneous or dermal tumor of the peripheral nerve sheath surrounding one or more nerve fascicles. It can occur in isolation or in patients with neurofibromatosis type 1. This tumor is usually benign although a small minority can undergo a malignant transformation. Diagnosis relies on ultrasound, computed tomography, magnetic resonance imaging, and histopathological evaluation.


The name plexiform neurofibroma (PN) is derived from its appearance in the form of a network or a plexus surrounding branches of a peripheral nerve. It is typically a benign tumor and is composed of Schwann cells, perineurial components, fibroblasts, and hematopoietic cells surrounded by collagenous or myxoid stroma [1]. Although it can occur anywhere on the body, the head and neck region are the commonest sites [2].

Clinically, patients present with an irregular, tortuous subcutaneous or dermal mass resembling a "bag of worms" [3]. Other symptoms and signs depend on the mass effect of this swelling and it is essential to exclude extrinsic compression on neighboring structures or bone abnormalities. Tissue damage can lead to pain and sensorimotor deficits even in benign PN [4].

Although a plexiform neurofibroma is not pathognomonic of neurofibromatosis type 1 (NF -1), it is suggestive of the condition as it is found in up to 30% patients with NF-1. So the physician should look for features of NF-1 in patients with a plexiform neurofibroma.

Approximately 5% of PN can undergo malignant transformation. These patients present with pain, neurological deficits, and a rapid tumor growth, especially during puberty and pregnancy [3].

  • The fine-needle aspiration cytology (FNAC) of the submandibular mass was inconclusive, but the FNAC of the swelling in the floor of the mouth revealed bland spindle cells in a haemorrhagic aspirate.[ecancer.org]
  • A CT-guided fine needle aspiration cytology of the right submandibular mass proved to be nondiagnostic.[ajnr.org]
  • With use of injection laryngoplasty for vocal cord medialization, which has been recently upgraded, vocal disorders and aspiration can be prevented.[jmedicalcasereports.com]
  • We encountered a 5-year-old child presenting with stridor and dyspnea, who had a diagnosis of laryngeal plexiform neurofibroma.[ncbi.nlm.nih.gov]
  • Patient 1 is a 7-year-old girl who first presented at age 2 months with biphasic stridor.[jamanetwork.com]
Progressive Dysphagia
  • The combination of large PNF and cervical spine dysplasia may cause compression of the upper gastrointestinal tract and chronic progressive dysphagia.[ncbi.nlm.nih.gov]
  • It causes a massive macroglossia that is progressive with advance of years and disturbs the patient's speech, occlusion, and tongue movements.[ncbi.nlm.nih.gov]
  • Derekoy et al reported a case of plexiform neurofibroma of the submandibular gland in a 20-year-old man with signs of Von Recklinghausen disease. 3 The patient also had macroglossia (regional gigantism).[ajnr.org]
Unilateral Proptosis
  • We present the case of a 52-year-old male with progressive, marked unilateral proptosis due to a multilobulated orbital mass, secondary to biopsy-proven plexiform neurofibroma (PN).[ncbi.nlm.nih.gov]
Foot Pain
  • We report the case of a patient who had severe foot pain, which progressively hampered her walking ability, erroneously attributed to recurrent Morton's neuroma.[ncbi.nlm.nih.gov]
Subcutaneous Mass
  • In conclusion, considering neurofibroma (NF) as differential diagnosis for subcutaneous masses in head and neck area is critical for early diagnosis and treatment procedure.[ncbi.nlm.nih.gov]
  • Clinically, it presents as a subcutaneous mass which feels like a "bag of worms". Most of the time, it is a superficial cutaneous/subcutaneous lesion, but it can occur almost anywhere in the body. Symptoms may be related to local mass effect.[radiopaedia.org]
  • Multiple subcutaneous masses are seen in the right pelvic region. No abnormal bones or internal organs are observed.[journal.ac]
Skin Discoloration
  • It is characterized by the overgrowth of nervous tissue and skin discoloration.[ncbi.nlm.nih.gov]
  • Hematoxylin- and eosin-stained sections showed unremarkable epidermis with slight hyperkeratosis.[ncbi.nlm.nih.gov]
Neck Mass
  • Biopsy of the left neck mass confirmed for plexiform neurofibroma. A careful search of the literature revealed no previous report of such an extensive neurofibroma in a premature neonate.[ncbi.nlm.nih.gov]
  • Patient 3 is a 7-year-old girl who presented to our otolaryngology clinic at age 7 months with a large left-sided neck mass and café au lait spots on her right neck ( Figure 3 A). She later developed an optic glioma.[jamanetwork.com]
Peripheral Neuropathy
  • Adverse reactions included transient somnolence in four, evanescent rash in two, and reversible mild peripheral neuropathy in two patients. Four patients showed less than 25% reduction in the tumor size.[n.neurology.org]
  • Peripheral neuropathy. 3 rd ed. Philadelphia: WB Saunders; 1993. p. 1623-39. [ Links ] 3. Nambi GI, Gupta AK, Kumaran S. Plexiform neurofibroma of the finger. J Plast Reconstr Aesthet Surg. 2008;61(11):1402-3. [ Links ] 4. Seddon HJ.[scielo.br]
Motor Disturbances
  • Herein, a case is reported in a 56-year-old man who also had muscle atrophy, severe motor disturbance, and mild sensory disturbance of the left leg due to childhood poliomyelitis.[ncbi.nlm.nih.gov]


Beside history and physical examination, the workup of PN depends on radiological studies and histopathological evaluation. Ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) are helpful in the diagnosis.

Ultrasonographic appearance is a target shaped mass with a hyperechoic center and resembling a cyst. However, the mass demonstrates a continuous peripheral nerve and this finding is confirmatory of a nerve sheath tumor [5]. Ultrasound cannot differentiate between a benign and malignant lesion.

MRI is the gold standard study as it is able to delineate the extent of the tumor as well as its origin from the nerve sheath [6]. Plexiform neurofibroma appears as a lesion in the form of a target with hyperintense T2 and a hypointense central signal [7]. MRI also helps to exclude sarcoma, schwannoma, lymphatic and venous malformations. In the case of a malignant transformation, the MRI will reveal an edematous zone around the lesion with cysts within the tumor while a tumor diameter exceeds five centimeters [8].

Positron emission tomography (PET) scan and CT scan can be performed if a biopsy is planned [9] [10].

Periostal Elevation
  • Magnetic resonance imaging (MRI) illustrated a single central fluid-fluid level and periosteal elevation with saucerisation of the anterior tibial cortex and mild surrounding oedema. Histopathology revealed a large plexiform neurofibroma.[ncbi.nlm.nih.gov]


  • A correct diagnosis is an essential starting point in the treatment of neurofibromas and a misdiagnosis may lead to an inappropriate treatment.[ncbi.nlm.nih.gov]
  • At present, there are no established criteria for the treatment of this rare lesion.[ncbi.nlm.nih.gov]
  • In conclusion, considering neurofibroma (NF) as differential diagnosis for subcutaneous masses in head and neck area is critical for early diagnosis and treatment procedure.[ncbi.nlm.nih.gov]
  • Various treatment modalities are considered to decrease pain. In this paper a case with plexiform neurofibroma causing severe pain and in whom alpha-interferon was used is presented.[ncbi.nlm.nih.gov]
  • Currently, surgical resection is still the treatment of choice though a management plan is not well defined. Patients need appropriate regular follow-up to detect malignancy or early recurrence.[ncbi.nlm.nih.gov]


  • […] health have better prognosis compared with those with poor health Age of the individual: Older individuals generally have poorer prognosis than younger individuals Individuals with bulky disease have a poorer prognosis Involvement of the lymph node can[dovemed.com]
  • MPNST are soft tissue sarcomas that arise from peripheral nerves, being one of the most aggressive malignancies in humans with extremely poor prognosis. MPNST frequently arise from a previously undetected plexiform neurofibroma (PNF).[ncbi.nlm.nih.gov]
  • PNFs can undergo malignant transformation to highly metastatic malignant peripheral nerve sheath tumors (MPNSTs) in 5-10% of NF1 patients, with poor prognosis. No effective systemic therapy is currently available for unresectable tumors.[ncbi.nlm.nih.gov]
  • MRI Reported signal characteristics include: T1: hypointense T2: hyperintense /- hypointense central focus ( target sign ) T1 C : mild enhancement Treatment and prognosis Although generally benign tumors, there is a significant potential for malignant[radiopaedia.org]


  • In addition, we review the literature with respect to etiology, current treatment strategies, and the issue of surveillance for this complex lesion occurring in the pediatric population.[ncbi.nlm.nih.gov]
  • Nerve Sheath Neoplasms/genetics Neurofibroma, Plexiform/drug therapy* Neurofibroma, Plexiform/etiology Neurofibroma, Plexiform/genetics Neurofibromatosis 1/complications Neurofibromatosis 1/genetics Neurofibromin 1/genetics Nuclear Proteins/metabolism[ncbi.nlm.nih.gov]
  • (Etiology) The cause of Plexiform Neurofibroma is due to genetic mutations.[dovemed.com]
  • The etiology of sporadic neurofibromas is unknown. Systemic Implications and Complications Solitary neurofibromas are benign and not associated with any systemic complications.[clinicaladvisor.com]
  • Neurofibromas can also be distinguished on histopathological examination by multiple different characteristics, including the presence of nerve fibers within the tumor. [10] Etiology Neurofibromas are peripheral nerve sheath neoplasms derived from a combination[eyewiki.aao.org]


  • Affiliations Department of Pediatrics University of Maryland, Baltimore, Maryland, USA Rosa Nguyen Department of Neurology, University Hospital Hamburg-Eppendorf, Hamburg, Germany Rosa Nguyen & Victor-Felix Mautner Department of Epidemiology and Public[nature.com]
  • Author information Affiliations Department of Pediatrics University of Maryland, Baltimore, Maryland, USA Rosa Nguyen Department of Neurology, University Hospital Hamburg-Eppendorf, Hamburg, Germany Rosa Nguyen & Victor-Felix Mautner Department of Epidemiology[nature.com]
  • Clinical and epidemiologic features in NF1 Neurofibromatosis: phenotype, natural history, and pathogenesis Friedman JM, Riccardi VM. Clinical and epidemiologic features in NF1. In: Riccardi VM, editor.[researchgate.net]
  • Epidemiology Both sex can be affected. Neurofibromas are rare in children, but start develop in puberty. Up to thousands of neurofibromas can develop in one adult NF1 patient.[atlasgeneticsoncology.org]
  • However, surgical resection has a risk of nerve injury, pain may persist after removal of the tumour(s) and tumours may regrow at the same site. [ 1 ] Epidemiology [ 6 ] Both type 1 and type 2 NF are inherited as autosomal dominant conditions but, for[patient.info]
Sex distribution
Age distribution


  • (A detailed review of what is known about the pathophysiology of various clinical features in NF1, including neurofibromas.) Packer, RJ, Gutmann, DH, Rubenstein, A, Viskochil, D, Zimmerman, RA.[clinicaladvisor.com]
  • In addition, information is included concerning the pathophysiology and pathology of the disorders being discussed, and some basic information concerning the causative genes (when appropriate).[euro-libris.ro]
  • We outline the pathophysiology of button battery-induced trauma and present key radiological features of button batteries that are important in preventing delayed diagnosis after pediatric ingestion.[researchgate.net]


  • Recognition of this disease process and differentiating it from malignant transformation can prevent unnecessary surgery.[ncbi.nlm.nih.gov]
  • This is of particular importance in children, to diagnose and treat unilateral high myopia early and prevent anisometropic amblyopia.[ncbi.nlm.nih.gov]
  • A complete excision of penile neurofibromas is mandatory to prevent recurrence or malignant degeneration and can be safely performed preserving the neurovascular bundle.[ncbi.nlm.nih.gov]
  • "Once we know the critical steps in the process, then we can design inhibitors to block each step in an effort to prevent or slow tumor formation."[news-medical.net]
  • Surgery is the first line treatment although the invasive nature of these tumors often prevents complete resection. Recent clinical trials have shown promising success for some drugs, notably selumetinib, an inhibitor of MAP kinase kinase (MEK).[ncbi.nlm.nih.gov]



  1. Marocchio LS, Oliveira DT, Pereira MC, et al. Sporadic and multiple neurofibromas in the head and neck region: a retrospective study of 33 years. Clin Oral Investig 2007;2013:165–169
  2. Ji Y, Xu B, Wang X, et al. Surgical treatment of giant plexiform neurofibroma associated with pectus excavatum. J Cardiothoracic Surg 2011;2013:119
  3. Murphey MD, Smith WS, Smith SE, Kransdorf MJ, Temple HT. From the archives of the AFIP: imaging of musculoskeletal neurogenic tumors: radiologic-pathologic correlation. Radiographics. 1999;19:5:1253–1280.
  4. Korf BR. Malignancy in neurofibromatosis type 1. Oncologist. 2000;5:6:477–485.
  5. Reynolds DL, Jacobson JA, Inampudi P, et al. Sonographic characteristics of peripheral nerve sheath tumors. American Journal of Roentgenology. 2004;182:3:741–744
  6. Fuchs B, Spinner RJ, Rock MG. Malignant peripheral nerve sheath tumors: an update. Journal of Surgical Orthopaedic Advances. 2005;14:4:168–174.
  7. Lin J, Martel W. Cross-sectional imaging of peripheral nerve sheath tumors: characteristic signs on CT, MR imaging, and sonography. American Journal of Roentgenology. 2001;176:1:75–82
  8. Wasa J, Nishida Y, Tsukushi S, et al. MRI features in the differentiation of malignant peripheral nerve sheath tumors and neurofibromas. American Journal of Roentgenology. 2010;194:6:1568–1574.
  9. Ferner RE, Golding JF, Smith M, et al. [18F]2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) as a diagnostic tool for neurofibromatosis 1 (NF1) associated malignant peripheral nerve sheath tumours (MPNSTs): a long-term clinical study. Annals of Oncology. 2008;19:2:390–394.
  10. Bredella MA, Torriani M, Hornicek F, et al. Value of PET in the assessment of patients with neurofibromatosis type I. American Journal of Roentgenology. 2007;189:4:928–935.

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Last updated: 2019-06-28 10:37