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Year : 2016  |  Volume : 22  |  Issue : 1  |  Page : 62-65

Neurofibroma of external auditory canal: An unusual differential diagnosis of aural polyp

1 Department of ENT and Head and Neck Surgery, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India
2 Department of Pathology, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India

Date of Web Publication16-Feb-2016

Correspondence Address:
Vijendra S Shenoy
Departments of ENT and Head and Neck Surgery, Kasturba Medical College Hospital, Manipal University, Attavar, Mangalore - 575 001, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-7749.176504

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Neurofibromas are circumscribed but nonencapsulated neoplasms of the nervous system. They are relatively common in the nervous system, but only a few have been reported in ear. Here, we report a case of a 38-year-old female who presented with the complaints of right ear pain and right ear obstruction. Examination revealed a mass in external auditory canal, which was excised by postauricular approach. Surgery resulted in an excellent functional outcome.

Keywords: External auditory canal, Neurofibroma, Polyp

How to cite this article:
Kamath PM, Shenoy VS, Deviprasad D, Lobo FD, Giri O. Neurofibroma of external auditory canal: An unusual differential diagnosis of aural polyp. Indian J Otol 2016;22:62-5

How to cite this URL:
Kamath PM, Shenoy VS, Deviprasad D, Lobo FD, Giri O. Neurofibroma of external auditory canal: An unusual differential diagnosis of aural polyp. Indian J Otol [serial online] 2016 [cited 2021 Jul 28];22:62-5. Available from: https://www.indianjotol.org/text.asp?2016/22/1/62/176504

  Introduction Top

Neurofibromatosis type 1 (NF-1) occurs in 1 in 2200–4000 live births.[1] It is an autosomal dominant condition with 70–80% penetrance. However, some cases of NF-1 also result from spontaneous mutations. The genetic defect has been linked to chromosome 17q11.2.[2] It is a multisystem genetic disease with cutaneous manifestations such as café-au-lait spots, freckles, and neurofibromas.[3] A diagnosis of NF-1, according to criteria established by the “National Institutes of Health” in 1987 and updated in 1990, depend on a careful clinical examination of the patient, his or her parents and siblings, and a detailed family medical history.[4] The plexiform neurofibroma, also named plexiform neuroma, pachydermatocele, or neurofibromatosis elephantiasis, has been classified as a benign tumor of peripheral nerve sheath involving multiple nerve fascicles. This is a highly vascularized, slow-growing, and locally invasive nonmetastatic tumor.[4] Plexiform neurofibroma is a complication of NF-1. It may occur in infancy and rarely after adolescence.[5] NF-2 is characterized by bilateral vestibular schwannomas whereas cutaneous manifestations are rare. Typical lesions of this condition are schwannomas that may be present in the acoustic nerve or in other cranial nerves (cranial nerve V and sometimes cranial nerve X) and meningiomas.[4] Other variants of NF-1 are a localized type and diffuse type. Localized-type neurofibroma is the most common type encountered in NF-1; typically, it is located in the dermis, but sometimes also extends to the superficial subcutaneous fat. Localized-type neurofibroma has been recognized as a slowly growing, small subcutaneous tumor that occurs in small nerve branches.[6],[7] Diffuse-type neurofibroma (DN) presents as a plaque-like elevation of the skin, and often arises in the head and neck region;[6] however, it is uncommon in the external auditory canal (EAC).[2] This diffuse-type of neurofibroma has ill-defined, infiltrative, cell-rich tumors that occupy the whole dermis and extend into the subcutaneous tissue. They envelope skin appendages and subcutaneous fat without destroying them.[7] Such latent features of DN make it difficult to remove the tumor without destroying normal anatomical structures, resulting in functional losses. NF-2 is characterized by bilateral vestibular schwannomas, rarely with cutaneous manifestations. Typical lesions are schwannomas that may be present in the acoustic nerve or in other cranial nerves (nerve V and sometimes nerve X) and meningiomas.[4]

  Case Report Top

A 38-year-old female presented in ENT outpatient department with complaints of pain in the right ear and right ear block for last 2 months. Ear examination revealed a mass in EAC, which was 4 mm × 4 mm in size. It occluded most of the ear canal, and tympanic membrane was only partially visible. On palpation with a probe, it was firm in consistency, nontender, and pedunculated. High-resolution computed tomography (CT) of temporal bone was done which showed soft tissue density in the right EAC abutting the tympanic membrane and causing a bulge medially in hypotympanum. The tympanic membrane being inseparable from the lesion [Figure 1] and [Figure 2]. Pure tone audiometry study was normal. The patient was taken up for surgery under general anesthesia and mass was removed by a postauricular approach. Intraoperatively, the mass was found to be attached to the posterior wall of the EAC [Figure 3] and [Figure 4]. After excision, the mass was sent for histopathological examination, which showed stratified squamous epithelium with foci of ulceration. The subepithelial tissue showed a partially circumscribed tumor comprising proliferating short fascicles and storiform pattern of elongate to spindle cells. The cells had elongated to ovoid nuclei with an excess of atypia and mitosis. The stroma showed focal myxoid area, rich vascular plexus, and foci of hyalinized collagen. Spicules of bone were seen within stroma. The resected margin showed the lesion. Final diagnosis was neurofibroma of EAC [Figure 5] and [Figure 6].
Figure 1: Computed tomography image showing soft tissue density in right external auditory canal

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Figure 2: Another computed tomography image showing soft tissue density in external auditory canal and hypotympanum

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Figure 3: Tumor mass as seen after postauricular exposure

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Figure 4: Resected tumor mass after surgery

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Figure 5: Low magnification microscopic picture showing partially circumscribed tumor comprising proliferating short fascicles and storiform pattern of elongate to spindle cells

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Figure 6: High magnification images showing stroma with focal myxoid area, rich vascular plexus, and foci of hyalinized collagen

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  Discussion Top

NF is one of the most common inherited disorders and can affect anyone, regardless of family history, race, gender, or ethnic background. Neurofibromas are tumors derived from Schwann cells, fibroblasts, and perineurial cells. They can be seen in any areas of body where nerve cells are present. This includes nerves just under the surface of the skin, as well as deeper nerves within the body, spinal cord, and/or brain. NF-1 is caused by a change in a gene carried on chromosome 17. The neurofibromas may turn into malignant neurofibrosarcomas. In NF-2, most commonly, neurofibromas are seen within the spinal cord or brain. Bilateral schwannomas of the acoustic nerve and multiple meningiomas are characteristic. NF-2 is caused by a change in a gene carried on chromosome 22. Solitary lesions are not usually associated with systemic manifestations unlike multiple lesions which are commonly seen in patients with NF or von Recklinghausen's disease.[8] Surgical management is the only viable therapy when a neurofibroma causes disability, intractable pain, or disfigurement.[9] The most challenging surgical aspect of these tumors is their infiltrative nature.[9] The surgical management of neurofibromas generally entails a concern: the extent of resection with respect to the probability of recurrence and loss of function.[9] Trevisani et al. have explained that “complete surgical excision of these lesions is virtually impossible; if not contraindicated.”[10] Crikelair and Cosman emphasized that amelioration rather than complete eradication should be the therapeutic goal.[11] In pediatric NF-1 patients, complete or near complete excision of the neurofibromas ensures recurrence rates of <20% and 40%, respectively, whereas subtotal resection (removal of 90% or less) leads to a recurrence rate of >60%.[12] Neurofibromas develop throughout life, but periods of hormonal activity in puberty and pregnancy are marked by the development of new tumors and acceleration of the growth of old ones.[9] To minimize the postoperative recurrence rate, it is important to resect the tumor to the greatest extent possible without causing postoperative functional loss. In our case, we removed the tumor along with a thin margin of surrounding skin. The wound healed well postoperatively and the patient was relieved of symptoms.

  Conclusion Top

Extracranial solitary neurofibromas, particularly, in the ear are rare. Clinical symptoms generally are due to tumor masses and increasing functional disorders or paresthesias as a result of nerve atrophy as tumor displaces nerve tissue. Diagnosis is based on clinical symptoms, CT, magnetic resonance imaging, and surgical biopsy with histological examination. Tumor must be resected completely, but postoperative functional disorders or cosmetic loss may often make a complete excision difficult. Recurrence after complete excision is rare, but can occur due to poorly encapsulated tumor formations.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Lustig LR, Jackler RK. Neurofibromatosis type i involving the external auditory canal. Otolaryngol Head Neck Surg 1996;114:299-307.  Back to cited text no. 1
Ferner RE. Neurofibromatosis 1 and neurofibromatosis 2: A twenty first century perspective. Lancet Neurol 2007;6:340-51.  Back to cited text no. 2
DeBella K, Szudek J, Friedman JM. Use of the National Institutes of Health criteria for diagnosis of neurofibromatosis 1 in children. Pediatrics 2000;105(3 Pt 1):608-14.  Back to cited text no. 3
Geller M, Bonalumi AF. Doenças genéticas em pediatria. In: Carakushansky G, editor. Neurofibromatose. 1st ed. Rio de Janeiro: Guanabara Koogan; 2001. p. 377-90.  Back to cited text no. 4
Waggoner DJ, Towbin J, Gottesman G, Gutmann DH. Clinic-based study of plexiform neurofibromas in neurofibromatosis 1. Am J Med Genet 2000;92:132-5.  Back to cited text no. 5
Enzinger FM, Weiss SW. Soft Tissue Tumors. 3rd ed. St. Louis, Missouri: Mosby Elsevier; 1995.  Back to cited text no. 6
Megahed M. Histopathological variants of neurofibroma. A study of 114 lesions. Am J Dermatopathol 1994;16:486-95.  Back to cited text no. 7
Coakley D, Atlas MD. Diffuse neurofibroma obstructing the external auditory meatus. J Laryngol Otol 1997;111:145-7.  Back to cited text no. 8
Manolidis S, Higuera S, Boyd V, Hollier LH. Single-stage total and near-total resection of massive pediatric head and neck neurofibromas. J Craniofac Surg 2006;17:506-10.  Back to cited text no. 9
Trevisani TP, Pohl AL, Matloub HS. Neurofibroma of the ear: Function and aesthetics. Plast Reconstr Surg 1982;70:217-9.  Back to cited text no. 10
Crikelair GF, Cosman B. Histologically benign, clinically malignant lesions of the head and neck. Plast Reconstr Surg 1968;42:343-53.  Back to cited text no. 11
Needle MN, Cnaan A, Dattilo J, Chatten J, Phillips PC, Shochat S, et al. Prognostic signs in the surgical management of plexiform neurofibroma: The children's hospital of Philadelphia experience, 1974-1994. J Pediatr 1997;131:678-82.  Back to cited text no. 12


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]


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