|Year : 2013 | Volume
| Issue : 4 | Page : 724-726
Intramural solitary fibrous tumor of the ileum: A case report and review of the literature
Yong-Qiao Liu1, Jun-Qiu Yue2
1 Department of Pathology, People's Hospital of Yingcheng, Yingcheng, China
2 Department of Pathology, Hubei Cancer Hospital, Hubei Province, China
|Date of Web Publication||11-Feb-2014|
Department of Pathology, Hubei Cancer Hospital, 116 Zhuodao Quan South Road, Wuhan 430079
Source of Support: None, Conflict of Interest: None
Solitary fibrous tumor (SFT) is a rare spindle cell tumor, which has never been reported to be derived from the wall of the small intestine. To describe a case of ileum intramural SFT. An ileum intramural SFT was observed in a healthy 26-year-old woman during cesarean section. Complete resection was performed to remove the tumor. Surgical specimens were used for pathological examination and immunohistochemistry, which confirmed the diagnosis of SFT. The patient had an uneventful recovery from the operation without any complications, recurrence, or metastasis during the 4-month follow-up. This report shows for the first time that SFT can occur in the intestinal wall and that complete resection can successfully remove the tumor with promising short-term prognosis. Thus, SFT should be considered in the differential diagnosis of any mesenchymal lesion arising from the gastrointestinal tract.
Keywords: Ileum, intestinal wall, solitary fibrous tumor
|How to cite this article:|
Liu YQ, Yue JQ. Intramural solitary fibrous tumor of the ileum: A case report and review of the literature. J Can Res Ther 2013;9:724-6
| > Introduction|| |
Solitary fibrous tumor (SFT) is a rare spindle cell tumor which was first described in the pleura by Klemperer and Robin in 1931.  By 2008, approximately 820 cases had been reported worldwide,  which occurs commonly in the pleura, but also rarely in extrapleural sites. SFT in the abdomen has been sporadically reported over the past decade. ,,, Moreover, Lucas and Ledgerwood in 2006  and Lau et al. in 2008,  each reported a case of SFT arising from the small bowel mesentery. However, there has been no report so far on SFT derived from the intestinal wall of the small intestine.
In this report, we describe a case of intramural SFT derived from the intestinal wall in a 26-year-old woman, which was accidentally observed during cesarean section.
| > Case Report|| |
A 26-year-old woman at 9 months plus pregnancy was referred to our hospital due to vaginal discharge. The patient previously had normal menstruation. The physical examination and electrocardiograph were normal. There were no laboratory abnormalities (blood glucose 5.6 mmol/L, alkaline phosphatase 287 U/L, leucine aminopeptidase 264.8 U/L, alanine aminotransferase 19.0 U/L, and cystatin C 1.14 mg/L).
While clearing the abdominal cavity after delivery of a healthy baby girl by the lower uterine segment cesarean section, the obstetrician observed a solid hard mass of the ileum, which was approximately 3.5 × 3.0 cm 2 in size. The patient's relatives were informed of the mass and agreed, with written informed consent, for a complete resection. After the operation, the excised tumor tissue was sent for pathological examination and immunohistochemistry.
The tumor was a well-encapsulated gray mass of size 3.5 × 3.0 × 3.0 cm 3 . The resected surface appeared to be off-white, homogenous, rubbery-like, and firm. The mass was covered by a brown membrane-like layer of tissue [Figure 1], which was confirmed to be the small intestinal mucosa by microscopic examination.
|Figure 1: Tumor was encapsulated gray mass of size 3.5 × 3.0 × 3.0 cm3, elastic hard, appears off-white in color at the resected surface, covered by small intestinal uosa|
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The tumor tissue was derived from the muscular layer of the ileum, with a relatively clear boundary, and its outer layer was covered by the intestinal mucosa [Figure 2]a. The tumor was composed of spindle-shaped cells, collagen fibers, and increased blood vessels [Figure 2]b. There were alternatively distributed hypocellular areas and hypercellular areas separated by thick hyaline degeneration of collagen fibers, which was similar to scarring tissue. In addition, branching hemangiopericytoma-like vascular proliferation was present in some areas.
|Figure 2: Histological examination with hematoxylin and eosin staining showing the tumor tissue located in the muscular layer, with a relatively clear boundary and the intestine mucosa as the outer lyer (Aa, original magnification ×4), and the keloid-like tissues and the proliferated micro-blood vessels area (Bb, original magnification ×20)|
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The tumor cells were positive for CD34 [Figure 3]a, CD99 [Figure 3]b, vimentin, and B-cell lymphoma 2 (BCL-2) protein staining, focally positive for p53 [Figure 3]c, but uniformly negative for CD117 [Figure 3]d, S-100 protein, and smooth muscle actin (SMA) [Figure 3]e. Based on these pathological and immunohistochemical results, the tumor was diagnosed as benign SFT of the ileum.
|Figure 3: Immunohistochemistry showing positive staining for CD34 (Aa), CD99 (Bb), and several cells positive for p53 (Cc), but negative for CD117 (Dd) and SMA (Ee)|
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The patient had an uneventful recovery from the operation. The patient was followed up for 4 months, without any complications. No tumor recurrence or metastasis occurred during this period of follow-up.
| > Discussion|| |
SFT is believed to originate from dendritic mesenchymal cells.  Schirosi et al. summarized the clinical characteristics, organizational structure, immunohistochemistry, fluorescence in situ hybridization analysis, mutation analysis, and epidemiology of pleural SFTs.  Although extrapleural SFTs share similar pathological and immunohistochemical characteristics with pleural SFTs, they may have different clinical manifestations. For example, approximately 70% of patients with pleural SFTs are females, whereas 50% of patients with extrapleural SFTs are females. 
The present case represents the first reported that originated from the wall of the ileum, indicating that SFT can occur in the intestinal wall. The uniqueness of this case is that the tumor was accidentally observed in a young woman during cesarean section. Since the patient did not present with any apparent intestinal symptoms before cesarean section and the tumor was resected right after cesarean section, no radiological, ultrasound or colonoscopic data for this case were available. There were no abnormalities in the levels of blood glucose, alkaline phosphatase, leucine aminopeptidase, alanine aminotransferase, and cystatin.
Schirosi et al. classified SFTs into three categories:  (1) keloid type, when the tumor mainly consists of hyperplasied collagen fibers; (2) mixed/conventional type, when the tumor alters the areas with a keloid-type appearance with the zones of hypercellularity; and (3) sarcoma type, when the tumor tissue shows increased cellularity as in a sarcoma. Based on this classification, our present case should be categorized under the mixed/conventional type.
Diagnosis of SFT must integrate results and analyses from gross pathology, microscopic pathology, and immunohistochemistry. It has been reported that SFTs are characteristically CD34 and CD99 positive, but CD117 negative.  CD117 antibody is the best marker to distinguish SFT from gastrointestinal stromal tumor (GIST), and immunohistochemistry for CD117 expression, especially when CD34 expression is positive, plays a very important role in the diagnosis of SFT. In the present case, the tumor was finally confirmed to be SFT by immunohistochemistry. Extrapleural SFTs might be difficult to distinguish from other soft tissue tumors. It is recommended that for all the spindle cell tumors that occur in the gastrointestinal tract, the differential diagnosis should be considered for GIST, smooth muscle tumors, and neurogenic tumors.
The appropriate therapy for SFT is complete surgical excision. SFT has the tendency to recur, mainly due to incomplete excision.  SFT has an unpredictable biological behavior. WHO classification  has categorized SFT into the middle type of tumors (occasionally metastatic). Approximately 20% of SFTs are malignant, generally characterized by size larger than 5.0 cm in diameter, with the mitoses of more than 4 per 10 high power fields, and necrosis.  Distant metastasis might occur in a small number of SFT cases, also mainly due to incomplete resection. 
The prognosis of extrapleural SFTs is unknown. It has been shown that tumor necrosis and increased expression of p53 and Ki-67 are valuable predictors for poor prognosis.  The present case did not show any evidence of recurrence or distant metastasis during the 4-month follow-up. The favorable prognosis of this patient is likely attributed to its benign nature. However, long-term monitoring is required to further determine the prognosis and verify the association between p53 protein expression and prognosis.
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[Figure 1], [Figure 2], [Figure 3]