A 47-year-old woman was admitted to the outpatient clinic with complaints of weakness and fatigue for the previous 3 months. She denied melena or hematemesis, but she had been given 3 units of erythrocyte transfusion 2 months before in another health institution. Her medical history was unremarkable other than diabetes mellitus for 7 years. Physical examination was normal other than tachycardia and cardiac systolic murmur. Initial laboratory findings showed the following: hemoglobin, 4.3 g/dl; white blood cells, 10.3x 10⁹/L; platelets, 239 x 10⁹/L; and ferritin, 2.4 ng/ml. Biochemical tests were normal. For the cause of anemia, upper gastroduodenal endoscopy was performed, which showed a giant semi-pedunculated polyp (11 cm) at the posterior wall of the gastric fundus (Figure 1). The mass had a large ulcer in the distal part (Figure 2). The mass was surgically removed (Figure 3). Postoperative pathology revealed a diagnosis of inflammatory fibroid polyp (IFP) (Figure 4). She was discharged on the third day following the operation. She was followed up for a further 14 months and is free of any symptoms.

FIGURE 1. Endoscopic appearance of a giant semi-pedunculated polyp at the posterior wall of the gastric fundus.

FIGURE 2. Endoscopic appearance of a big ulcer at the distal part of the ulcer.

FIGURE 3. Macroscopic appearance of an inflammatory fibroid polyp.

FIGURE 4. Pathological appearance of an inflammatory fibroid polyp.

Background

IFPs are rare, mesenchymal, benign lesions originating from the submucosa of the gastrointestinal (GI) tract that are usually semi-pedunculated and covered by normal mucosa. They can originate anywhere in the GI tract, being most commonly seen in the stomach (80%), followed by the small bowel, rectum, colon, and esophagus. In the stomach, they are usually located in the antrum or prepyloric region and very seldom in the gastric fundus (Zhang, Cui, Xing, Yunfei, & Xiangqian, 2014). Gastric IFPs are described as firm, solitary, sessile, or pedunculated. IFPs larger than 1 cm in diameter may have a depression or ulceration at the surface of the overlying mucosa (Chongsrisawat, Yimyeam, Wisedopas, Viravaidya, & Poovorawan, 2004).

IFPs are present in all age groups, with a maximal incidence in the sixth decade, and being slightly more common in women. Most IFPs are smaller than 5 cm, but as in our case, they can grow up to 11 cm (Chongsrisawat et al., 2004; Zhang et al., 2014). Most are small and asymptomatic but can show clinical manifestations (depending on the tumor location and size) such as intestinal obstruction, intussusceptions, abdominal pain, nausea, vomiting and constipation, iron deficiency anemia, and rarely GI bleeding (He, Shen, Fang, Sun, & Qin, 2013; Zhang et al., 2014).

Diagnosis is difficult before surgery, and the histological findings of a biopsy specimen are usually hard to diagnose. In addition, differentiation may be very difficult, especially between IFPs and GI stromal tumors (Zhang et al., 2014).

Physical examination is usually unremarkable. Imaging, such as upper GI series, ultrasonography, computed tomography, and magnetic resonance imaging, can help diagnose the mass (Chongsrisawat et al., 2004). Endoscopic ultrasonography is useful to rule out other lesions located beneath the mucosa. The characteristic endoscopic ultrasonographic appearance of IFPs shows an indistinct margin, hypoechoic homogeneous lesion, and location within the second and/or third layers with an intact fourth layer. However, the final diagnosis is generally based on endoscopy and histological examination (Matsushita, Hajiro, Okazaki, & Takakuwa, 1997).

The etiology and pathogenesis of IFPs are still unclear. It has been hypothesized that several factors such as chemical, mechanical, and biological agents could damage the GI mucosa and hence stimulate the formation of polyps in certain people. IFP is a specific response of GI stromal tissue to an unknown etiology (Chongsrisawat et al., 2004). It was thought to occur due to the response of a peculiar type of granulation tissue. Recent studies have detected the role of platelet-derived growth factor receptor and alpha polypeptide (PDGFRA) mutations in exons 12 and 18 in the formation of small intestinal IFPs. IFPs may therefore be classified as PDGFRA-driven benign neoplasms (Shalom, Wasserman, Segal, & Orda, 2000). An electron microscopic study revealed that IFP represents a reactive lesion of myofibroblastic nature (Navas-Palacios, Colina-Ruizdelgado, Sanchez-Larrea, & Cortes-Cansino, 1983). Hence, some authors assume that IFP is not a neoplasia, but a reactive process, either to an allergy or a foreign body, and has no malignant potential (Chongsrisawat et al., 2004).

Histologically, an IFP is characterized by an onion-skin pattern of proliferation of fibroblasts around small blood vessels with marked eosinophilic infiltration (He et al., 2013). It may be highlighted by immunohistochemistry staining for CD34 (He et al., 2013).

Small lesions may be removed endoscopically. However, exploratory laparotomy is the treatment of choice if the tumor is very large or if there is a suspicion of malignancy (Hattori et al., 2008). IFPs usually do not recur after complete resection, and adjunct therapies are unnecessary. All of the clinical findings and symptoms resolve after resection (Chongsrisawat et al., 2004; Matsushita et al., 1997).

Summary

IFPs are rare disorders, and they generally follow a benign course. Gastric IFPs may present with several clinical features including nausea, vomiting, and iron deficiency anemia, but rarely present with massive digestive tract hemorrhage. This must be kept in mind when evaluating uncertain etiology of GI hemorrhage.

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