Saudi Journal of Gastroenterology
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CASE REPORT Table of Contents   
Year : 1996  |  Volume : 2  |  Issue : 3  |  Page : 164-167
Schwannoma of the rectum: A case report


Department of Surgery, Riyadh Central Hospital, Riyadh, Saudi Arabia

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Date of Submission18-Oct-1995
Date of Acceptance14-May-1996
 

How to cite this article:
Qasi SA, Sabir EI. Schwannoma of the rectum: A case report. Saudi J Gastroenterol 1996;2:164-7

How to cite this URL:
Qasi SA, Sabir EI. Schwannoma of the rectum: A case report. Saudi J Gastroenterol [serial online] 1996 [cited 2019 Nov 21];2:164-7. Available from: http://www.saudijgastro.com/text.asp?1996/2/3/164/34024


Schwannoma (Neurilemmoma) is a tumor of the peripheral nerves. It arises from the outer layer of the neurilemmal sheath of the schwann cell [1] . It is seldom malignant [1],[2] . It is a rare tumor. Although it comprises only 1 % of the head & neck tumors, this remains their commonest site in the body [2] . It is rare in the gastrointestinal tract, total number of cases reported between 1981-1994 were 45. We, herein report a case of rectal schwannoma at an even rarer site among the gastrointestinal schwannomata. We also include a review of literature.

We are reporting this case because of three reasons:

  1. It is a rare tumor at a very rare site.
  2. The diagnosis may be difficult if there are malignant changes.
  3. Accordingly, the treatment may be very easy or very difficult (simple enucleation or radical operation), the latter means abdomino-perineal resection [3],[4] .



   Case Report Top


H.A.A. is a 29-years-old Saudi female. She presented with dyspareunia, difficulty in passing stool and constipation. The pain is deep and lasts 2-4 hours. The constipation lasts 4-6 days associated with sensation of fullness in the rectum and a persistent desire to defecate. All these symptoms were on and off for six years. She has no mucus or blood discharge from the rectum, no vaginal discharge and no loss of weight. Systemic review was normal.

She has a past history of similar attacks for which she had many gynecological and surgical consultations. She was admitted to Riyadh Central Hospital five years ago. Transrectal needle biopsy at that time showed spindle-shaped cells with pallissading of nuclei and prominent verocay bodies, with no evidence of malignancy. She was discharged against medical advice at that time.

Her family and social history was not significant. She is married for eight years, but had no children. She had normal menarche and menstrual periods.

Examination showed a well built young female with stable vital signs. All systems were normal. Rectal examination revealed a smooth mass, 5 cm. in diameter, 3 cm. from the anal verge. It is in the right posterolateral wall of the rectum. It is firm, mobile and not tender. The anal mucosa was felt normal over it.

Routine investigations were all normal. Ultrasound of the abdomen and pelvis was normal. Barium enema showed smooth mass indentation of the distal rectum, with normal caliber and mucosal surfaces of the rectum and colon. Intravenous urogram was normal. Double contrast computerized axial tomogram showed a soft tissue mass, 5 cm in diameter in the right posterolateral wall of the rectum. No perirectal extension and no enlarged lymphnodes [Figure - 1].

Accordingly, she was offered an operation for excision of the tumor, but the patient and her husband were very hesitant and she escaped from the hospital twice. At last she accepted the operation. The consent was signed for a probably radical operation, this was based on the possibility of local recurrence, anal incontinence and the very rare probability of malignant transformation.

Bowl preparation with oral mannitol (200 ml. of 20% solution) was started and she was taken to the theater under antibiotic cover (gentamicin and metronidazole). In a lithotomy position, the right ischiorectal fossa was approached through a curvilinear pararectal incision, 8 cm in length.

Dissection showed a white bosselated mass, well encapsulated. It is inseparable from the right rectal wall. The inferior rectal nerve was seen traversing the mass, and the puborectalis muscle was lateral to it [Figure - 2].

The mass was excised totally with intact capsule. The nerve was sacrificed. Histopathology showed a greyish white lobulated mass, cut sections showed areas of hemorrhage. The microscopic description showed hyalinised stroma of spindle shaped cells arranged in two nodules. There is pallissading of nuclei and verocay bodies. The impression was hyalinised schwannoma [Figure - 3].

She had a smooth postoperative course. She had a good sphincter tone and continence for both feces and flatus. She was started on normal diet on the second day and she was discharged on the seventh day. No abnormalities were observed during her follow up of two years after the operation.


   Discussion Top


The schwannoma is a tumor of neural crest origin [Figure - 4] [1] . Both schwannoma and neurofibroma arise from the schwann cells. Schwann cells are glia-like cells found along the peripheral nerves. The myelin sheath is a protein-lipid complex made up of many layers of the cell membrane of schwann cells. Histologically they are well developed cylindrical bands and connective tissue fibers.

There are 3 types:

  1. Pallissading of nuclei with clear cytoplasm (verocay bodies), and this is called Antony type A [5] .
  2. Loosely arranged stroma, no distinctive pattern, and this is called Antony type B [5] .
  3. Mixed schwannoma.


The malignant transformation in schwannoma is very rare (0.3%) [1] . The rapid growth is an indication of malignancy. It is very difficult to differentiate between neurogenic sarcoma and neurofibrosarcoma histologically unless a nerve trunk is identified. So a good cooperation between the surgeon and the pathologist is needed. The malignant schwannoma usually spreads to the lungs and two-thirds of them recur locally. Most of them present with pressure symptoms, many are discovered accidentally and a few present with a mass which may be painful or painless.

Treatment consists of enucleation if it is benign, or enblock resection if malignant. Cure rate is 80% in well differentiated tumors, and 20% in undifferentiated ones.

The computer-generated ' abstracts between 1981-1994 showed that only 45 cases of gastrointestinal schwannomata had been reported, [Table - 1]. Of these, only two are related to this case.

Arcidiaco et at (1981), reported a case of rectal schwannoma from Italy. He discussed the diagnostic and therapeutic modalities and stressed on radical operation because of recurrence, malignant changes and the difficulty of making a concrete benign diagnosis [1] . Terada et al reported a case of vaginal schwannoma. This was detected using ultrasound and magnetic resonance imaging. S100 protein was detected in the tumor cells [4] . He stresses on that this is a very slowly growing tumor, its early detection is very difficult even histologically.

The commonest are gastric schwannoma [3] . Their danger is that of torrential uncontrolled hemorrhage and the diagnosis is usually made after laparotomy and histopathological examination. A few of them present with abdominal mass, dyspepsia, anemia or abdominal pain. Some are associated with Von-Recklinghausen's disease and neurofibromatosis of the gastrointestinal tract, plexiform neurofibroma of the myocardium or pheochromocytoma [6] .

Endoscopy can be valuable in the diagnosis of these tumors. Pathology will confirm the pallissading of nuclei, verocay bodies, spindle­shaped cells and hyalinised vessels. Electron microscopy and immunohistochemical studies are valuable in diagnosis. Complete excision is the preferred treatment.

Small intestinal tumors commonly present with melena and hematemesis, [7],[8] abdominal mass or fatigue and anemia [9] . No correct diagnosis can be done preoperatively, selective angiography can localize some lesions but fails in the majority of them, this is because many of the tumors are either intramural or subserosal. Some tumors are diagnosed by immunohistochemical reactions like S 100 protein and neutral cell adhesion molecules [9] .

Some schwannomata are associated with Hodgkin's disease. Some are in multiple sites in the GIT like the pancreas, the stomach and small intestine. They are usually associated with Von-Recklinghausen's disease, and present with GIT bleeding [10] .

Our management of this patient was based on the clinically benign course of the disease through a period of six years. This was coupled with the benign preoperative histopathology report. Both were combined with the simple and easy access to the tumor.

 
   References Top

1.Cuschieri A. Essential Surgical Practice, 2nd edition. Wright 1988;353.  Back to cited text no. 1    
2.Batsakis JG. Tumors of the Head and Neck. Williams and Wilkins 1974;231-3.  Back to cited text no. 2    
3.Arcidiaco M, Uggeri G, Rumi A, Valenti I. Schwannoma of the Rectum: A clinico-therapeutic study. Minerva Chir 1981;36(4):267-72.  Back to cited text no. 3    
4.Terada S, Suzuki N, Tomimatsu N, Akasofu K. Vaginal schwannoma. Arch Gynecol Obstet 1992;251(4):203-6.  Back to cited text no. 4    
5.Coulson WF. Surgical Pathology, Vol 2, Lippingcot 1978;1331-3.  Back to cited text no. 5    
6.Croker JR, Greenstein RJ. Malignant schwannoma of the stomach in a patient with Von-Recklinghausen's disease; Bibliographic Citation. Histopathology 1979;3(1):79-85.  Back to cited text no. 6    
7.Bigliani S, Lanfranchi M, Vitale L, Kiss A, Drago GW, Berardengo E. A bleeding jejunal schwannoma. Minerva Chir 1993;48(7):359-62.  Back to cited text no. 7    
8.Eskelinen M, Pasanen P, Kosma Vm, Alhava E. Primary malignant schwannoma of the small bowel. Ann Chir Gynaecol 1992;81(3):326-8.  Back to cited text no. 8    
9.Miettinen M, Cupo W. Neural cell adhesion molecule distribution in soft tissue tumor. Hum Pathol 1993;24 (1):62-6.  Back to cited text no. 9    
10.Walsh MM, Brandspigel. Gastrointestinal bleeding due to pancreatic schwannowa. Gastroenterology 1989;97 (6):1550-1.  Back to cited text no. 10    

Top
Correspondence Address:
Shabir A Qasi
Consultant Surgeon Riyadh Centra. Hospital, P.O. Box 2897, Riyadh 11197
Saudi Arabia
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Source of Support: None, Conflict of Interest: None


PMID: 19864827

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    Figures

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