SRM Journal of Research in Dental Sciences

CASE REPORT
Year
: 2013  |  Volume : 4  |  Issue : 1  |  Page : 25--28

Plexiform (multinodular) neurilemoma of the tongue


Rekha B Chaudhari 
 Department of Oral Pathology and Microbiology, Government Dental College and Hospital, Nagpur, Maharashtra, India

Correspondence Address:
Rekha B Chaudhari
Department of Oral Pathology and Microbiology, Government Dental College and Hospital, Nagpur, Maharashtra
India

Abstract

Neurilemoma is an uncommon nerve sheath tumor, arising from schwann cells. Typically it occurs as a solitary, asymptomatic, slow growing benign tumor. Its etiology is unknown. Microscopically two distinct patterns are pathognomic - Antoni A and Antoni B tissue. The current case report describes an unusual neurilemoma of the tongue, in a young 24-year-old female. Histologically it exhibited plexiform (multinodular) pattern. ItSQs review and histomorphological features of this rare variant are discussed.



How to cite this article:
Chaudhari RB. Plexiform (multinodular) neurilemoma of the tongue.SRM J Res Dent Sci 2013;4:25-28


How to cite this URL:
Chaudhari RB. Plexiform (multinodular) neurilemoma of the tongue. SRM J Res Dent Sci [serial online] 2013 [cited 2022 Nov 29 ];4:25-28
Available from: https://www.srmjrds.in/text.asp?2013/4/1/25/116821


Full Text

 Introduction



Neurilemoma (schwannoma) is a benign nerve sheath neoplasm, arising from schwann cells with a predilection for head and neck region. [1] It was first identified by Virchow in 1908. [2] The etiology is unknown. Intraoral schwannoma accounts for 1% of all head and neck tumors. It usually occurs as a solitary soft-tissue lesion or intrabony lesion. Tongue is involved most frequently followed by palate, floor of the mouth and buccal mucosa. [3]

The tumor may occur at any age, but is more commonly found in the 2 nd and 3 rd decades of the life. [3],[4] There is no gender preference. The majority of neurilemoma are asymptomatic. [1] Clinically oral neurilemoma may occur in two basic forms. The first most common is an encapsulated well-defined firm sub-mucosal nodule that is freely movable, resembling cyst. The other presentation is a pedunculated or dome like projection arising from mucosal surface, mimicking fibroma. Either may be ulcerated secondary to trauma. [5] It is an encapsulated nerve sheath tumor consisting of two components; a highly ordered cellular component (Antoni A area) and a loose myxoid component (Antoni B).

The purpose of this article is to highlight the unusual plexiform (multinodular) pattern of schwannoma.

 Case Report



A young 24-year-old female reported to Govt. Dental College and Hospital, Nagpur for evaluation of nodular mass near the tip of the tongue, with 1½ years duration. Patient was normal in built, conscious and co-operative. Clinical examination disclosed a sessile, well-circumscribed nodular mass with lobular appearance anteriorly and approximately 2 cm × 2.5 cm in size, near the apex of the tongue extending to the left lateral surface and anterior ventral area [Figure 1] and [Figure 2]. The swelling was non-tender, non-ulcerated, with slightly inflamed surface and firm to elastic in consistency. Regional lymph nodes were not palpable. The patient's medical and family history was unremarkable. She had no any other swelling in other parts of the body. There was no history of palpitations, hypertension, sweating, headache, flushing and diabetes. The presumptive differential diagnosis included - adenoma, benign mesenchymal tumor - fibroma, lipoma. Excisional biopsy was performed. The healing was uneventful. There was no recurrence after 1-year follow-up.{Figure 1}{Figure 2}

Gross pathology of the specimens - one soft-tissue oval mass of 2 cm × 1.5 cm size, cut surface was white grayish in color.

Histopathological examination of the encapsulated tumor mass revealed, multinodular areas, exhibiting Antoni A and Antoni B type tissue. A thin fibrous tissue appeared surrounding the nodules, whereas many of them appeared interconnected by it [Figure 3]. These nodular areas were of varying sizes and shapes - round, oval kidney and club [Figure 4] and [Figure 5]. Few appeared merging with one another, forming a large lobule. Two characteristic histomorphological (Antoni A and Antoni B) patterns were seen within the nodules. Antoni A type was composed of compact cells with spindle shaped nuclei arranged in well-organized palisaded pattern. Acellular zones known as Verocay bodies were frequently seen surrounded by palisaded zones [Figure 6]. This pattern was predominant. Other part illustrated loosely textured matrix - Antoni B [Figure 3].{Figure 3}{Figure 4}{Figure 5}{Figure 6}

On the basis of these features it was diagnosed as plexiform (multinodular) schwannoma of the tongue.

 Discussion



Neurilemoma (schwannoma) is a benign encapsulated, slow growing tumor, arising from nerve sheath's schwann cells. [1] Although it is the most frequently encountered peripheral nerve sheath tumor in the oral cavity, it is nonetheless relatively uncommon. Clinically neurilemoma presents as a solitary circumscribed nodule, rarely being multinodular. [4] Female sex predilection was reported by Ferreti et al. However no gender preponderance is mentioned in the literature. Neurilemoma generally demonstrates a characteristic microscopic appearance. The hallmark of neurilemoma is the pattern of alternate Antoni A and Antoni B areas. Antoni A areas are composed of compact cells that usually have twisted nuclei. They are arranged in short bundles or interlacing fascicles. In highly differentiated areas there may be nuclear palisading, whirling of the cells and Verocay bodies, formed by two compact rows of well aligned nuclei separated by fibrillary cell processes. [1] This was well-illustrated in this case. Antoni B exhibits disorderly arrangement of cells, distributed in loose connective tissue. The involvement of the tongue, size of the lesion (less than 5 cm), slow growing nature and its occurrence in young female and histological features seem to be compatible with diagnosis of neurilemoma.

The most unusual aspect of the present case was demonstration of multinodular plexiform pattern. About 5% of neurilemoma grow in plexiform or multinodular pattern which may or may not be apparent macroscopically. [1] The finding of several distinctly separate nodules is consistent with earlier reports. [3],[4],[6],[7],[8],[9],[10] Individual nodules exhibited diagnostic Antoni A and Antoni B components. Some of them were oval, kidney shaped, club shaped. Such varied patterns (dumbbell, club) were also noted by Argenyi et al. in their series of cutaneous neuromas. [11] Number of nodules varied in different reports - 4-50 in a series by Fletcher and Davies, 2 were noted by Ferreti et al., whereas 10-12 were observed in the present case. In the present case, interconnection between nodules was also illustrated [Figure 1]. However, frequent interconnections between adjacent nodules were noted by Heifetz et al. [8] in their report of neurilemoma in parotid area. Few appeared merging with one another to form a large mass. This finding is similar to that observed by Krolls et al. and Barbosa and Hansen. Serial sections throughout the specimen maintained multinodular appearance as noted previously. [3],[7]

The issue of distinguishing multinodular versus plexiform appearance was discussed by Krolls et al. [3] and Heifetz et al. [8] The term was used interchangeably by Fletcher and Davies. [6] Iwashita and Munetoma used the term "multinodular" to denote multinodular plexiform neurilemoma. Solitary plexiform schwannoma is characterized by thin capsule, fascicles and multiple interconnecting nodules with presence of Antoni A and focal or absent Antoni B areas. [3] Plexiform neurofibroma comprises the elements of normal nerve fibers but in a highly irregular pattern. In plexiform neurofibroma, the matrix is myxoid in early stages and contains tortuous intertwined cords of schwann cells. [12] Palisaded encapsulated neuroma (PEN) microscopically shows capsule which surrounds fascicles of spindle shaped cells with prominent nuclei which have tendency to palisading to give the tumor superficial resemblance to schwanoma. [12] The presence of axons in the tumor distinguishes it from schwannoma. [12] Verocay bodies are frequent in solitary plexiform schwannoma and absent in PEN. [3]

As the present case reveals multiple distinct separate nodules and many interconnecting nodules, thin capsule, prominent Antoni A areas, frequent Verocay bodies - the term plexiform (multinodular) neurilemoma seems to be proper to describe this lesion. Recurrence was reported in earlier reports. [3],[4],[10] However, it does not appear to have sinister prognosis. S-100 protein is valuable for diagnosis of neurilemoma, especially when there is degeneration in it, when myxoid change or fibrous tissue obscures the neoplastic neural tissue. Small slow growing painless lumps in and around the oral cavity are frequently found. Such lesions may present difficulty in diagnosis. Differential diagnosis of these seldom includes neurilemoma. Hence all such lesions should be completely removed and subjected to histopathological examination for revealing the nature of the lesion.

References

1Enzinger FM, Weiss SM. Soft tissue tumors. 3 rd ed. St. Louis, Missouri: Mosby; 1995. p. 829-38.
2Ranhbar M, Mardanpour K. Lingual schwannoma: A case report. Iran Red Crescent Med J 2009;11:454-6.
3Krolls SO, McGinnis JP Jr, Quon D. Multinodular versus plexiform neurilemoma of the hard palate. Report of a case. Oral Surg Oral Med Oral Pathol 1994;77:154-7.
4Ferreti Bonan PR, Martelli H Jr, Nogueira Dos Santos LA, Comini Mol V, Paes De Almeida O. Multinodular neurilemmoma of the tongue: A case report with differential immunohistochemical profile. Minerva Stomatol 2008;57:71-5.
5Crawford WH Jr, Korchin L, Greskovich FJ Jr. Neurilemmomas of the oral cavity: Report of five cases. J Oral Surg 1968;26:651-8.
6Fletcher CD, Davies SE. Benign plexiform (multinodular) schwannoma: A rare tumour unassociated with neurofibromatosis. Histopathology 1986;10:971-80.
7Barbosa J, Hansen LS. Solitary multilobular schwannoma of the oral cavity. J Oral Med 1984;39:232-5.
8Heifetz SA, Sadove AM, Joyner ML, Davidson D. Intraoral plexiform (multinodular) neurilemoma. Pediatr Pathol 1991;11:457-65.
9Iwashita T, Enjoji M. Plexiform neurilemmoma: A clinicopathological and immunohistochemical analysis of 23 tumours from 20 patients. Virchows Arch A Pathol Anat Histopathol 1987;411:305-9.
10Hashiba Y, Nozaki S, Yoshizawa K, Noguchi N, Nakagawa K, Yamamoto E. Recurrent multinodular neurilemmoma of the female upper lip. Int J Oral Maxillofac Surg 2007;36:171-3.
11Argenyi ZB, Cooper PH, Santa Cruz D. Plexiform and other unusual variants of palisaded encapsulated neuroma. J Cutan Pathol 1993;20:34-9.
12Cawson RA, Binnie NH, Eveson JW. Colour atlas of oral diseases. 2 nd ed. London: Wolfe publishing, an imprint of Mosby- Year Book Europe Limited.; 1994. p. 10.15.