Sultan Qaboos University Med J, May 2013, Vol. 13, Iss. 2, pp. E330-333, Epub. 9th May 13 Submitted 13TH Sep 12 Revision. 11TH Nov 12, Revision Recd. 16TH Nov 12 Accepted 12TH Dec 12 Departments of 1Surgery and 2Pathology, Sultan Qaboos University Hospital, Muscat, Oman *Corresponding Author e-mail: drkhalidmunirbhatti@yahoo.com أورام شوان اللفائفّية غري املصحوبة بأعراض تعرض كورم مساريقي تقرير حالة ومراجعة األدبيات �شاهزاد يونا�ض خان، خالد منري بهاتي، �رسيدهاران كوليدان امللخ�ص: ورم �شوان اللفائفي هو ورم حميد ين�شاأ من خاليا �شوان يف اجلهاز الع�شبي املركزي اأو الطريف. املواقع الأكرث�شيوعا ت�شمل الراأ�ض والأطراف. من النادر اأن ين�شاأ هذا الورم من ال�شفرية الع�شبية للقناة اله�شمية. ومن الأندر اأن يكون موقع املن�شاأ هو دقاق الأمعاء الدقيقة. نقدم يف هذا التقرير حالة مري�ض لديه كتلة مركزية يف البطن كان قد مت ت�شخي�شها قبل اجلراحة كورم م�شاريقي. ومع ذلك، اأثبت ت�شخي�ض الِكيْمياُء الن�شيجية امَلناِعَيّة للعينة امل�شتاأ�شلة جراحيا باأن الورم هو ورم �شوان اللفائفي. مفتاح الكلمات: خاليا �شوان؛ حالت �شاذة؛ ورم غمد الليف الع�شبي؛ كي�ض م�شاريقي؛ الأورام اللفائفية؛ البطن تقرير حالة؛ عمان. abstract: A schwannoma is a benign tumour which arises from the schwann cells of the central or peripheral nervous system. Common sites include the head and limbs; it is rare that this tumour arises from the gastrointestinal tract’s neural plexus. It is even rarer to find the ileum as the site of origin. We report a patient who presented with a central abdominal mass which was preoperatively diagnosed as a mesenteric tumour. However, immunohistochemistry of the surgically-removed specimen proved it to be a benign ileal schwannoma. Keywords: Schwann Cells, abnormalities; Neurilemmoma; Mesenteric Cyst; Ileal Neoplasms; Abdomen; Case Report; Oman. Asymptomatic Ileal Schwannoma presenting as a Mesenteric Tumour Case report and review of literature Shahzad Y. Khan,1 *Khalid M. Bhatti,1 Sreedharan V. Koliyadan,1 Marwa Al Riyami2 online Case report A schwannoma is usually a benign, encapsulated neoplasm which arises from the Schwann cells of the peripheral, autonomic or cranial nerves. The most common site for presentation is the 8th cranial nerve.1 Schwannomas of the gastrointestinal (GI) tract are rare; even if present within the abdomen, the most common site is the stomach.2 Only a few cases of benign ileal schwannomma have been reported in the literature.3–14 We report a case of ileal schwannoma where the patient presented with an abdominal mass and discomfort. Case Report A 37-year-old male presented with an abdominal mass which had arisen the previous week. There were no obstructive or other associated symptoms. His past medical and surgical history included a laparoscopic hernia repair 7 years previously; his family history was unremarkable. An abdominal examination revealed an 18 x 16 cm non-tender mass in the umbilical region, firm in consistency and dull on percussion, with no visceromegaly or ascites. The external genitalia, per rectal examination and the rest of the systemic examination were normal. A mesenteric or a retroperitoneal tumour was considered clinically as the initial diagnosis. The patient’s haemoglobin level was 14.4 g/ dl. He had a normal coagulation profile and a total leukocyte count. His blood sugar level was 4.5 mmol/L, blood urea was 3.1 mmol/L, serum creatinine was 79 µmol/L and his liver function tests were normal (ALT [alanine aminotransferase] 48 IU/L, AST [aspartate aminotransferase] 24 u/L, total bilirubin 4 µmol/L). An ultrasound scan showed a large heterogeneous mass of unidentified origin with internal vascularity. A computed tomography (CT) scan of the abdomen with intravenous and oral contrast showed a mesenteric Shahzad Y. Khan,Khalid M. Bhatti, Sreedharan V. Koliyadan and Marwa Al Riyami Case Report | 331 mass of 15 x 14 x 11 cm, with faint enhancement, and central necrosis with no calcification [Figure 1]. The mass was abutting the ascending colon and the hepatic flexure. There was no vascular enhancement or lymph node involvement. An ultrasound-guided true-cut biopsy was performed and showed a low- grade spindle cell lesion suggestive of fibromatosis, myofibromatosis, a solitary fibrous tumour or a benign nerve sheath tumour. Exploratory laparotomy findings revealed a well-encapsulated 2 Kg tumour in the mesentery of the ileum, with an adherent ileocaecal junction and the appendix stretched over the tumour [Figure 2]. No retroperitoneal infiltration or mesenteric lymph adenopathy was seen. The liver, spleen and the rest of the viscera were normal. A resection of the tumour, along with a limited right hemicolectomy and an end-to-end ileocolic anastomosis, were performed. His recovery was uneventful. Histopathological examination showed a segment of the small bowel with an un-encapsulated neoplasm present within the muscularis propria of the ileum, and extending outwards into the serosa. The neoplasm was composed of bland spindle cells with tapered elongated nuclei, and a scattering of plumper nuclei with pale chromatin and small distinct nucleoli [Figure 3]. Immunohistochemical markers showed a diffuse positivity of S-100, with variable intensity, ranging from moderate to focally strong, highlighting the areas of neural differentiation. The cells were also strongly positive for neurospecific enolase (NSE). The diffuse positivity of S-100 favoured the diagnosis of schwannoma. The recovery of the patient was uneventful, and he was discharged on the 7th postoperative day. The one year follow-up showed no recurrence. Discussion Ileal schwannomas usually present with abdominal pain,11 but may also present with other complications; melena,9,11 degeneration,4,6 and intussusception5,10,13 having also been reported [Table 1]. This case presented with an abdominal mass without obstructive symptoms. A review of the limited available literature showed that it was the first case to present asymptomatically. A preoperative diagnosis is quite difficult.11 An ultrasound (US) may show a mass of variable echogenicity. There is no consensus on the CT findings of ileal schwannomas, as, in reported cases, CT was non-diagnostic and showed only a mass.11 Magnetic resonance imaging (MRI), as reported by Nagi,11 may show a submucosal tumour; however, the findings were again nonspecific. In cases Figure 1 A&B: Computerised tomography scans, from the axial (A) and coronal (B) view, of the mass in the ileocaecal region without obstruction. Figure 2: The mass in the ileocaecal region. Figure 3: The top images show an unencapsulated spindle cell neoplasm involving the muscularis propria of the bowel wall (arrow). Under high magnification, it is formed of fascicles of bland spindle cells. The tumour cells are positive for S-100 (lower left image) with darker staining nerve bundles highlighted. Neurospecific enolase is also positive (lower right image). Asymptomatic Ileal Schwannoma presenting as a Mesenteric Tumour Case report and review of literature 332 | SQU Medical Journal, May 2013, Volume 13, Issue 2 presenting with melena blood, a scintigraphy11 or angiography may be of help. In these cases, upper or lower GI endoscopies may rule out other causes of GI haemorrhage. In the present case, an US- guided biopsy was supposed to assist in making a decision; however, the results were inconclusive. Nevertheless, an US-guided biopsy may rule out lymphomas, in which case surgery could be avoided. Spilling, a rupture of the mass, or seeding of the malignant tumour are a few of the theoretical risks associated with a US-guided biopsy of any intra- abdominal mass. The preoperative differentiation between a benign or malignant schwannoma by a flourodeoxyglucose positron emission tomography (FDG-PET) scan15 has been proposed by some authors, but its application in diagnosing an ileal schwannoma has not yet been established. The gold standard is a histopathological examination of the surgically-removed specimen. With electron microscopy, spindle-shaped cells are characteristic, with areas of hyper- and pauci-cellularity). Immunohistochemistry confirms a schwannoma if the staining for S-100 protein is positive. The mainstay of treatment is a surgical resection and an end-to-end anastomosis. The extent of the resection will depend upon the location of the tumour. If, after the ileal resection, a sufficient length of the dista ileum is available for ileo-ileal anastomosis, continuity should be restored by anastomosing the two ends. In our case, location was so distal in the ileum that we had to proceed with a limited right hemicolectomy. Histopathological analysis has a major role in the further management of such cases. In cases of benign ileal schwannomas, no recurrence has yet been reported;11 however, lifelong surveillance will be required in cases of malignant ileal schwannomas. Conclusion The ileal schwannoma is a rare entity with variable presentation, and arriving at a preoperative diagnosis is usually challenging. In cases presenting without complication, a resection and an anastomosis of the ileal is the treatment of choice. References 1. Darrouzet V, Martel J, Enée V, Bébéar JP, Guérin J. Vestibular schwannoma surgery outcomes: Our multidisciplinary experience in 400 cases over 17 years. Laryngoscope 2004; 114:681–8. Table 1: A review of the literature on schwannomas Name of Study Year of publication Origin of study No. of cases reported/reviewed Presentation Cornette De St-Cyr M, et al.** 1958 France 1 - Poulat r, et al.** 1963 France 1 Degeneration Intraperitoneal bleeding Maison E.** 1969 France 1 Ileo-ileal invagination Filimon C, et al.** 1974 Romania 1 Degeneration Ilieve H.** 1977 Croatia 1 - Gourtsoyiannis NC, et al.* 1993 Greece 1 - Jadhav rN, et al.* 1996 Mumbai (India) 1 Bleeding per rectum Insegno W, et al. 1996 Genova 1 Intussception in pregnancy Nagal t, et al. 2003 Beppu (Japan) 5 Adbominal Pain = 3 Melena = 2 rangiah DS, et al.* 2004 Australia 1 - Hirasaki S, et al. 2008 Japan 1 Ileocolic intussception târcoveanu E, et al.* 2011 Romania 1 - * = abstract only; ** = no abstract. Shahzad Y. Khan,Khalid M. Bhatti, Sreedharan V. Koliyadan and Marwa Al Riyami Case Report | 333 2. Voltaggio L, Murray R, Lasota J, Miettinen M. Gastric schwannoma: a clinicopathologic study of 51 cases and critical review of the literature. Hum Pathol 2012; 43:650–9. 3. Cornette De St-Cyr M, Callens C. Enormous abdominal tumor having as starting point the termination of the ileum (neurinoma). Maroc Med 1958; 37:1034–5. 4. Poulat R, Grandmottet P. Intraperitoneal hemorrhage caused by rupture of a degenerated schwannoma of the ileum. Resection, recovery. Arch Mal Appar Dig Mal Nutr 1963; 52:359–61. 5. Maison E. Schwannoma of the small intestine and ileo-ileal invagination. Sem Hop 1969; 45:1210–11. 6. Filimon C, Vanţă M. Degenerated schwannoma of the ileum. Chirurgia (Bucur) 1974; 23:37–41. 7. Iliev H. Neurinoma of the small intestine. Acta Chir Iugosl 1977; 24:297–302. 8. Gourtsoyiannis NC, Bays D, Papaioannou N, Theotokas J, Barouxis G, Karabelas T. Benign tumors of the small intestine: preoperative evaluation with a barium infusion technique. Eur J Radiol 1993; 16:115–25. 9. Jadhav RN, Bapat RD, Rohondia OS, Joshi AS, Bhatt P. Bleeding ileal schwannoma. Indian J Gastroenterol 1996; 15:149. 10. Insegno W, Fiorone E, Castrati G, Turtulici G, Palladino M. Intestinal intussusception in pregnancy with obstruction, caused by benign neurilemmoma. Role of abdominal echocardiography in the preoperative diagnosis. Minerva Ginecol 1996; 48:505–9. 11. Nagai T, Fujiyoshi K, Takahashi K, Torishima R, Nakashima H, Uchida Am, et al. Ileal schwannoma in which blood loss scintigraphy was useful for diagnosis. Intern Med 2003; 42:1178–82. 12. Rangiah DS, Cox M, Richardson M, Tompsett E, Crawford M. Small bowel tumours: a 10 year experience in four Sydney teaching hospitals. ANZ J Surg 2004; 74:788–92. 13. Hirasaki S, Kanzaki H, Fujita K, Suzuki S, Kobayashi K, Suzuki H, et al. Schwannoma developing into ileocolic intussusception. World J Gastroenterol 2008; 14:638–40. 14. Târcoveanu E, Georgescu S, Vasilescu A, Dănilă N, Lupaşcu C, Dimofte G, et al. Small bowel tumours from barium meal to capsule endoscopy and from open to laparoscopic approach. Chirurgia 2011; 106:451–64. 15. Beaulieu S, Rubin B, Djang D, Conrad E, Turcotte E, Janet F. Early positron emission tomography of schwannomas: Emphasizing its potential in preoperative planning. AJR 2004; 182:971–4.