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An Official Publication of the Indian Association of Oral and Maxillofacial Pathologists


 
  Table of Contents    
CASE REPORT  
Year : 2013  |  Volume : 17  |  Issue : 3  |  Page : 447-450
 

Ancient neurilemmoma: A rare oral tumor


1 Department of Oral and Maxillofacial Pathology, Sri Venkateswara Dental College and Hospital, Thalambur, Chennai, Tamil Nadu, India
2 Department of Oral and Maxillofacial Surgery, Sri Venkateswara Dental College and Hospital, Thalambur, Chennai, Tamil Nadu, India

Date of Web Publication17-Jan-2014

Correspondence Address:
J Muruganandhan
Department of Oral and Maxillofacial Pathology, Sri Venkateswara Dental College and Hospital, Thalambur, Near Navalur, Off OMR, Chennai - 603 103, Tamil Nadu
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0973-029X.125218

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   Abstract 

Neurilemmomas are benign tumors of neural origin composed of Schwann cell proliferation in characteristic patterns. Ancient neurilemmomas are usually longstanding growths that exhibit degenerative features that could be mistaken for malignancy. They are extremely rare in the oral cavity and present in older individuals of long duration. The authors report a case of ancient neurilemmoma in a young patient with short duration of growth. This unique case presented with remarkable histopathological features with respect to vascularity and atypia associated with degenerative change. It is essential to not mistake these features as malignant transformation so as to avoid radical procedures.


Keywords: Ancient schwannoma, neurilemmoma, neural tumor


How to cite this article:
Muruganandhan J, Prasad T S, Selvakumar T, Kumar S N. Ancient neurilemmoma: A rare oral tumor. J Oral Maxillofac Pathol 2013;17:447-50

How to cite this URL:
Muruganandhan J, Prasad T S, Selvakumar T, Kumar S N. Ancient neurilemmoma: A rare oral tumor. J Oral Maxillofac Pathol [serial online] 2013 [cited 2018 Nov 16];17:447-50. Available from: http://www.jomfp.in/text.asp?2013/17/3/447/125218



   Introduction Top


Oral schwannomas are uncommon benign tumors, composed of Schwann cell proliferation. The microscopic picture is characteristic, described as a spindle cell lesion with Antoni A and Antoni B arrangements. [1],[2],[3],[4],[5] Some lesions named "ancient," present with degenerative features. Oral ancient schwannomas are exceedingly rare. [6],[7],[8],[9],[10] The management and clinical behavior is the same as classic schwannoma. Recurrence is rare. We report a case of ancient schwannoma highlighting the histopathology. The unique feature in our report is the short duration of the tumor in a young patient, which might raise suspicion of malignancy.


   Case Report Top


A 22-year-old male patient reported to the dental facility with a growth in the right back tooth region of his mouth, He had noticed the start of the growth 6 months ago. The lesion was stated to be painless and slow growing. On intraoral examination there was a nodular soft tissue mass in the mucobuccal fold region, in the right posterior maxillary quadrant above the molars. It was about 2 × 2 cm in size, smooth, sessile, non-tender and firm on palpation, with slight bleeding on manipulation. A provisional diagnosis of pyogenic granuloma was made [Figure 1]a]. The patient consented to surgical excision and the surgery was performed after general clinical and routine laboratory investigations. He is being followed-up regularly for the past 3 months and progress has been uneventful.
Figure 1: Clinical photograph of the oral lesion (a). Cut section of the excised specimen showing the solid and hemorrhagic areas (b)

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The cut-section of the excised tissue revealed a solid lesion with hemorrhagic areas [Figure 1]b. On histopathological examination, the lesion presented as a circumscribed cellular mass [Figure 2]. The cells were mostly spindle shaped with oval/blunt elongated nuclei. They were arranged in two patterns. One pattern was a palisaded arrangement of cells encircling eosinophilic structures (suggestive of Verocay bodies) [Figure 3]; and the other pattern was an irregularly arranged configuration of spindle cells, sometimes in a loose myxoid background [Figure 4]a and b. These patterns appeared consistent with descriptions of Antoni A and Antoni B patterns observed in schwannomas. There was significant vascularity throughout the lesion, with thick-walled blood vessels surrounded by hyalinization and inflammatory cells [Figure 5]a and b]. Extravasated red blood cells (RBCs), hemosiderin deposition and siderophages were occasionally encountered [Figure 6]. In some areas, the spindle cells revealed nuclear pleomorphism and increased nuclear cytoplasmic ratio [Figure 7]a and b. Mitotic activity was insignificant, with mitotic index (MI) <1 per high power field (HPF). No abnormal or bizarre mitotic figures were observed.
Figure 2: Photomicrograph of the circumscribed lesion (H&E stain, 40)

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Figure 3: Photomicrographs of the Antoni A areas. (H&E stain, 100)

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Figure 4 (a and b): Photomicrographs of the Antoni B areas. (H&E stain, ×100)

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Figure 5: Photomicrographs of the vascularity (a) and prominent hyalinization and inflammatory infiltrate (b) (H&E stain, 100)

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Figure 6: Photomicrographs of the large vessels with hemorrhage and hemosiderin. (H&E stain, ×40)

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Figure 7 (a and b): Photomicrographs of the cellular atypia. (H&E stain, ×400)

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Taking into account the above features of schwannoma, along with extensive hemorrhage, hemosiderin deposition and cellular atypia, a histopathological diagnosis of ancient schwannoma was given.


   Discussion Top


The schwannoma is a benign tumor of the neural Schwann cells that can potentially occur in any part of the body. It is said to develop from the neural sheaths of cranial (except optic and olfactory), peripheral motor, sensory and sympathetic nerves. [1] Up to 25% may be associated with Von Recklinghausen's Neurofibromatosis II (NFM II). In the head and neck region (25-45% cases) it can involve the facial soft tissues, sinuses, nasal and oral cavities, parotid, pharynx and cervical nerve trunks. [2] Oral cavity tumors are quite uncommon, comprising up to 1% of the total. [3],[4] The ancient variety is extremely rare in the oral cavity, with only 16 cases reported so far. [5],[6],[7],[8],[9],[10] The oral schwannoma is seen mostly in the tongue but can occur in the labial and buccal mucosa, palate, vestibules, etc., It usually presents as a slowly enlarging nodule. [3],[4]

Histopathologically, the tumor is biphasic, consisting of Antoni A and Antoni B patterns. Antoni A pattern consists of fascicles of palisaded bipolar Schwann cells streaming around acellular eosinophilic areas. These cells usually have oval or blunt elongated nuclei. The acellular zones assuming organoid shape are termed Verocay bodies. The Antoni B pattern is less cellular, with randomly arranged cells in a loose myxoid stroma. Associated nerve and neurites may be seen peripherally, but are not a part of the tumor. Vascularity is also a feature of schwannomas. [1],[2],[3],[4],[5]

Some workers classify schwannomas into five types: common type, plexiform, cellular, epithelioid and ancient. The plexiform schwannoma has a multinodular growth pattern, which is cellular and prone to recurrence. The cellular schwannoma has a predominant Antoni A pattern with atypical features and increased mitosis. Both of these types are benign and should not be mistaken for sarcomas. [1],[11]

In lesions where hemorrhage, hemosiderin deposition and chronic inflammatory changes are observed with pleomorphic cells, the term ancient schwannoma is given. The ancient schwannoma was described first by Ackerman and Taylor in 1951. The oral ancient schwannoma was first reported by Eversoll and Howell in 1971. [6] Only few cases have been reported in the oral cavity. In all these reports the patients were in their 4 th decade of life or older. The mean age of occurrence was 43 years and the usual size of the tumor ranged from 0.9 to 5.5 cm. The average duration of presentation was 10 years, but in some cases 2-5 month duration had been noted. [6],[7],[8],[9] The microscopic alterations reported were cystic degeneration, prominent myxoid areas, bizarre spindle cells and occasional mitoses. The atypical changes are due to degeneration and should not be misconstrued as malignancy. Large hyalinized thick-walled blood vessels, hemorrhagic foci, lipid laden and hemosiderin-laden histiocytes are not uncommon. The cells themselves are spindle shaped, with eosinophilic cytoplasm and tapered nuclei; some of which are pleomorphic and hyperchromatic. Necrosis can be seen. Immunohistochemistry may be performed to confirm the diagnosis. [11],[12]

Malignant peripheral nerve sheath tumor (MPNST) is a malignancy of neural tissue, whose histological features resemble the fibrosarcoma. Microscopic evidence of invasion is required for diagnosis. Frequent local recurrence and distant metastasis are part of its typical biological behavior. [13],[14],[15] In the present case, the diagnosis of ancient schwannoma was made due to the presence of cellular atypia, vascular pattern, hemorrhage, and hemosiderin accumulation; notwithstanding the duration of only 6 months. Factors apart from chronicity may be responsible for the atypical changes observed in this case.

Schwannomas stain strongly with S-100 (97%), Leu-7 (57%) and myelin basic protein (MBP) (44%), confirming their neural origin. However, neurofilament (NF) is usually negative due to absence of neurites. This feature can distinguish schwannomas from the neurofibroma, where nerve fibers are a part of the tumor. [6] CD 56 and calretinin are usually positive in schwannomas, while CD 34 and Factor XIIIa are positive in neurofibromas. These markers can be included in the panel in doubtful cases. In case of MPNSTs, S-100 is usually positive, except in the perineural variant, where epithelial membrane antigen (EMA) showed strong reaction in perineural cells. Markers of proliferation like increased MIB-1 labeling, p53 overexpression and loss of retinoblastoma (RB) protein expression have been found in MPNST case series. [13],[14],[15]

Electron microscopy shows bipolar cells with long cytoplasmic processes, entangled with extracellular matrix like collagen and basement membrane material characteristic of Schwann cells. The stroma sometimes consists of long-spaced collagen bundles with a 130 nm banding pattern, which are termed Luse bodies. [12],[16]


   Conclusion Top


Schwannomas, including the ancient variety, are treated by surgical excision. Recurrence is rare. Ancient schwannomas may be mistaken for malignant change; therefore deeper knowledge of this variety is crucial to avoid unnecessary surgery. Most cases of recurrence are due to inadequate excision, and some are associated with NFM-I1 or Multiple endocrine neoplasia (MEN) type III. [1],[16]

 
   References Top

1.Weiss SW, Goldblum JR. Parotid schwannoma. In: Enzinger SW, Weiss SW, editors. Enzinger and Weiss's Soft Tissue Tumors. 4 th ed. Mosby: Saint Louis Missoury; 2001. p. 1146-67.  Back to cited text no. 1
    
2.Handschel J, Heikaus S, Depprich R, Kübler NR, Yekta SS, Smeets R, et al. Intraoral schwannoma: review of the literature and presentation of a rare case. Cranio 2012;30:150-3.  Back to cited text no. 2
    
3.Wright BA, Jackson D. Neural tumors of the oral cavity: a review of the spectrum of benign and malignant oral tumors of the oral cavity and jaws. Oral Surg Oral Med Oral Pathol 1980;49:509-22.  Back to cited text no. 3
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4.Martins MD, Anunciato de Jesus L, Fernandes KP, Bussadori SK, Taghloubi SA, Martins MA. Intra-oral schwannoma: case report and literature review. Indian J Dent Res 2009;20:121-5.  Back to cited text no. 4
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5.Pfeifle R, Baur DA, Paulino A, Helman J. Schwannoma of the tongue: report of 2 cases. J Oral Maxillofac Surg 2001;59:802-4.  Back to cited text no. 5
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6.Chen CY, Wang WC, Chen CH, Chen YK, Lin LM. Ancient schwannoma of the mouth floor - A case report and review. Oral Oncol Extra 2006;42:281-5.  Back to cited text no. 6
    
7.Shilpa B. Ancient schwannoma - a rare case. Ethiop J Health Sci 2012;22:215-8.  Back to cited text no. 7
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8.Subhashraj K, Balanand S, Pajaniammalle S. Ancient schwannoma arising from mental nerve. A case report and review. Med Oral Patol Oral Cir Bucal 2009;14:E12-4.  Back to cited text no. 8
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9.Gainza-Cirauqui ML, Eguía-Del Valle A, Martínez-Conde R, Coca-Meneses JC, Aguirre-Urizar JM. Ancient schwannoma of the hard palate. An uncommon case report and review. J Clin Exp Dent 2013;5:e62-5. Available from: http://www.medicinaoral.com/odo/volumenes/v5i1/jcedv5i1p62.pdf.  Back to cited text no. 9
    
10.Kim NR, Chung DH, Park DS, Kim DW, Lee SC, Kim SY, et al. Ancient schwannoma in oral cavity: report of two cases. J Korean Assoc Oral Maxillofac Surg 2011;37:530-4.  Back to cited text no. 10
    
11.Bhalerao S, Chhabra R, Tamgadge A, Tamgadge S. Cellular schwannoma of oral cavity: a case report. Int J Oral Maxillofac Pathol 2012;3:22-5.  Back to cited text no. 11
    
12.White W, Shiu MH, Rosenblum MK, Erlandson RA, Woodruff JM. Cellular schwannoma. A clinicopathologic study of 57 patients and 58 tumors. Cancer 1990;66:1266-75.  Back to cited text no. 12
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13.Yamazaki H, Tsukinoki K, Shimamura K, Kaneko A. Malignant peripheral nerve sheath tumor with perineurial cell differentiation arising from the tongue. Oral Oncol Extra 2005;41:77-80.  Back to cited text no. 13
    
14.Bagan JV, Sanchis JM, Jimenez Y, Murillo J, Poveda R, Diaz JM. Malignant peripheral nerve sheath tumor of the maxilla. Oral Oncol Extra 2005;41:70-3.  Back to cited text no. 14
    
15.Mawrin C, Kirches E, Boltze C, Dietzmann K, Roessner A, Schneider-Stock R. Immunohistochemical and molecular analysis of p53, RB, and PTEN in malignant peripheral nerve sheath tumors. Virchows Arch 2002;440:610-5.  Back to cited text no. 15
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16.Marx RE, Stern D. Oral and maxillofacial pathology. A rationale for diagnosis and treatment. Illinois: Quintessence Publishing; 2003. p. 359-61.  Back to cited text no. 16
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]



 

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    Abstract
   Introduction
   Case Report
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