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CORRESPONDENCE
Year : 2014  |  Volume : 10  |  Issue : 2  |  Page : 368-370

Retroperitoneal ancient schwannoma: Two cases and review of literature


1 Department of Surgical Oncology, Yashoda Cancer Institute, Hyderabad, Andhra Pradesh, India
2 Department of Pathology, Yashoda Hospitals, Hyderabad, Andhra Pradesh, India

Date of Web Publication14-Jul-2014

Correspondence Address:
Ranganath Ratnagiri
Division of Surgical Oncology, Yashoda Cancer Institute, Raj Bhavan Road, Somajiguda - 500 082, Hyderabad, Andhra Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0973-1482.136660

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 > Abstract 

Ancient Schwannomas are rare variants of tumors which arise from the peri-neural Schwann cells. These tumors are termed "ancient" because of the degenerative features acquired with increasing age in these tumors. They are benign, slow growing and usually detected only incidentally or due to local symptoms. Some tumors may demonstrate nuclear atypia, and may be mistakenly termed malignant. Malignant change is usually associated with von Recklinghausen's syndrome in 5% to 18% of cases. Retroperitoneal schwannomas account for only 0.5% to 5% of all cases and are extremely uncommon. They are well encapsulated and recurrences following complete surgical excision are uncommon.

 > Abstract in Chinese 

2例腹膜后古老神经鞘瘤:报告及文献回顾
摘要
古老神经鞘瘤是从周围神经的雪旺氏细胞产生的肿瘤罕见变异体。这些肿瘤被称为“古老”因为在这些肿瘤中退行性功能获得性随着年龄而增加。这种类型肿瘤通常为良性的,生长缓慢,多为偶然或由于局部症状发现。其中一些肿瘤可显示核异型,并可能被错误地称为恶性。5%至18%的病例中,恶性变化通常与von Recklinghausen氏综合征相关。腹膜后神经鞘瘤只占0.5%到5%非常少见,一般包膜完整,手术切除后极少复发。
关键词:古老,腹膜后腔,神经鞘瘤


Keywords: Ancient, retroperitoneum, schwannoma


How to cite this article:
Ratnagiri R, Mallikarjun S. Retroperitoneal ancient schwannoma: Two cases and review of literature. J Can Res Ther 2014;10:368-70

How to cite this URL:
Ratnagiri R, Mallikarjun S. Retroperitoneal ancient schwannoma: Two cases and review of literature. J Can Res Ther [serial online] 2014 [cited 2019 Nov 18];10:368-70. Available from: http://www.cancerjournal.net/text.asp?2014/10/2/368/136660


 > Background Top


Schwannomas are benign peripheral nerve sheath tumors, which are most common in females, between the second and fifth decades of life. [1] They occur most often in the head and neck and in the extremities. They are an uncommon cause of a retroperitoneal mass and are classically well-encapsulated and vascular. [2] Malignant transformation is extremely rare. The term "ancient schwannoma" refers to the degenerative changes, which occur in these tumors with increasing duration (age). [2],[3] Nuclear atypia may also be present in these tumors and may be mistaken for malignant change.

Complete surgical resection results in cure and recurrences are uncommon.

We describe two cases of retroperitoneal ancient schwannomas treated at our Institute over the past 2 years.


 > CASE REPORTs Top


Case 1

A 45-year-old lady presented to us with complaints of left upper quadrant abdominal pain, and perception of a mass in the same site for 3 months. There were no other symptoms. Clinical examination revealed a firm mass in the left hypochondrium with no mobility. A computed tomography (CT) scan revealed a 10 × 8 × 6 cm retroperitoneal tumor, with no evidence of regional or distant metastases [Figure 1]a. The patient underwent a resection of the tumor and had an uneventful post-operative recovery. The gross appearance of the tumor was that of a mixed solid and cystic lesion and the final histopathology was ancient schwannoma [Figure 1]b.
Figure 1

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Follow-up: The patient has completed 2 years on follow-up and is clinically asymptomatic and radiologically disease free.

Case 2

A 50-year-old lady presented to us with left sided flank pain of 1 month duration. Clinical examination was unremarkable. A CT scan revealed a 20 × 15 × 12 cm cystic tumor with solid areas, which seemed to arise from the lower pole of the left kidney. A radical nephrectomy was planned. Intraoperatively, the tumor was found to arise from the retroperitoneum and was infiltrating the left kidney. A radical en bloc resection of the tumor with the left kidney was performed.

Pathology revealed an ancient schwannoma with cystic degeneration and atypical cells [Figure 2].
Figure 2: H and E stained tumor showing the characteristic Antoni A and B areas (×10)

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Follow-up: The patient has completed 15 months follow-up and remains disease free.


 > Discussion Top


Schwannomas or neurilemmomas are benign soft-tissue tumors, which arise from Schwann cells of the peripheral nerve sheaths. They usually arise from sensory nerves; however, motor nerve origin has also been reported. [4] The most common sites of origin are the head and neck and the extremities. [4] Retroperitoneal schwannomas are rare and account for 0.3% to 3.2% of these tumors. [5] Due to the large loose areolar space available, these tumors present late with compression effects and degenerative changes. Classically, therefore, the clinical course is slow and protracted and malignant change is uncommon. They are encapsulated and on histology display the distinctive Antoni A areas, which are highly cellular and Antoni B areas of myxoid stroma. [6] Spindle shaped cells arranged in palisades, whorls or in parallel lines are characteristic of Antoni A areas, whereas a hypocellular myxoid matrix denotes the Antoni B areas.

Ancient schwannomas are a rare variant described by Ackerman and Taylor in 1951. [7] They constitute 0.8% of all soft-tissue tumors. They are characterized by distinctive degenerative tumor features such as cystic degeneration, fibrosis, stromal edema, xanthomatous change, and perivascular hyalinization. Degenerative nuclear changes such as pleomorphism, lobulation, and hyperchromasia may also be seen in these tumors. [7] All these changes have been attributed to the duration of growth ("aging") of the tumor, and consequent vascular insufficiency-hence the term "ancient schwannoma." Despite these changes, ancient schwannomas behave similarly to their conventional counterparts.

On microscopy, ancient schwannomas show areas of cellularity intermixed with myxoid matrix like other conventional schwannomas. The cellular regions however tend to be sclerosed or fibrotic and in time may undergo degenerative changes leading to hematomas and cysts. [8] Nuclear palisades seen in classic schwannomas are absent. Nuclear atypia and hyperchromasia is common and was also noted in both our cases. Differentiation from malignancy can be made by noting the absence of mitoses and the preservation of cohesive clusters of spindle shaped cells. Flow cytometry assessing the deoxyribonucleic acid ploidy may also help in confirming the benign nature of these tumors. [8] Diffuse positivity on immunostaining with S 100 is also a feature of these tumors because of their neural origin.

These tumors present with symptoms of compression such as pain, numbness etc., and need surgical excision for establishing a definitive diagnosis. Complete surgical resection of the tumor with preservation of the surrounding structures, if possible will result in cure. [8]

We have described two cases of an unusual pathological entity, ancient schwannoma arising in the retroperitoneum. These are slow growing, indolent benign tumors, which present with pressure symptoms. Surgical resection results in cure and if there is a suspicion of the diagnosis before surgery, all surrounding structures have to be preserved as recurrences are uncommon.

 
 > References Top

1.Choudry HA, Nikfarjam M, Liang JJ, Kimchi ET, Conter R, Gusani NJ, et al. Diagnosis and management of retroperitoneal ancient schwannomas. World J Surg Oncol 2009;7:12.  Back to cited text no. 1
    
2.Loke TK, Yuen NW, Lo KK, Lo J, Chan JC. Retroperitoneal ancient schwannoma: Review of clinico-radiological features. Australas Radiol 1998;42:136-8.  Back to cited text no. 2
    
3.Dahl I. Ancient neurilemmoma (schwannoma). Acta Pathol Microbiol Scand 1977;85:812-8.  Back to cited text no. 3
    
4.Jayaraj SM, Levine T, Frosh AC, Almeyda JS. Ancient schwannoma masquerading as parotid pleomorphic adenoma. J Laryngol Otol 1997;111:1088-90.  Back to cited text no. 4
    
5.Hughes MJ, Thomas JM, Fisher C, Moskovic EC. Imaging features of retroperitoneal and pelvic schwannomas. Clin Radiol 2005;60:886-93.  Back to cited text no. 5
    
6.Graviet S, Sinclair G, Kajani N. Ancient schwannoma of the foot. J Foot Ankle Surg 1995;34:46-50.  Back to cited text no. 6
    
7.Ackerman LV, Taylor FH. Neurogenous tumors within the thorax; a clinicopathological evaluation of forty-eight cases. Cancer 1951;4:669-91.  Back to cited text no. 7
[PUBMED]    
8.Gubbay AD, Moschilla G, Gray BN, Thompson I. Retroperitoneal schwannoma: A case series and review. Aust N Z J Surg 1995;65:197-200.  Back to cited text no. 8
    


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