Inflammatory pseudotumor (IPT) is a rare benign tumor of unknown etiology that can occur in almost any organ system. It has neoplastic features such as local recurrence, invasive growth, and vascular invasion, leading to the possibility of malignant sarcomatous changes. The clinical presentations of colonic IPT may include abdominal pain, anemia, a palpable mass, and intestinal obstruction. A few cases of colonic IPT have been reported, but colonic IPT with pedunculated morphology is very rare. Furthermore, since it can mimic malignant polyps, understanding the endoscopic findings of colonic IPT is important for proper treatment. Herein, we present a case of colonic IPT with pseudosarcomatous changes, presenting as a large polyp, mimicking a malignant polyp in the cecum, along with a literature review.
Inflammatory pseudotumor (IPT) is a rare benign tumor that has been synonymously referred to as a plasma cell granuloma or inflammatory myofibroblastic tumor.
Here, we report an uncommon case of colonic IPT presenting as a large pedunculated polyp, mimicking a malignant polyp in the cecum. We also reviewed the endoscopic findings of reported cases in the literature.
A 32-year-old female patient with no underlying disease was admitted to a local clinic complaining of right lower quadrant pain that persisted for 2 weeks. Abdominal computed tomography (CT) performed at a local hospital revealed a soft-tissue mass, measuring approximately 4 cm, and increased colonic wall thickness in the ascending colon and cecum (
The patient’s postoperative course was uneventful, and she was discharged on the fifth postoperative day. She did not have any complications during the 8-month follow-up period.
IPT is a rare benign lesion. Histologically, it is characterized by dominant spindle cell proliferation with acute and chronic inflammatory cells.
Colonic IPT is rare. In the study by Höhne et al.,
In our case, a 32-year-old female patient presented with intermittent abdominal pain in the right lower quadrant with intussusception. The preoperative colonoscopy and abdominal CT findings suggested a malignant polyp. The cause of IPT was obscured in our case. However, considering the abundant neutrophil and pleomorphic cell infiltration, an acute inflammation caused by bacterial or viral infection was suspected. The patient underwent surgical resection. The mass resected from the cecum was a polypoid lesion (4.5×3.8×2.2 cm) with a pedunculated morphology. Colonic IPTs are often misdiagnosed as colonic carcinoma on abdominal CT, especially in older adults.
Endoscopic differential diagnosis of colonic IPT includes colon cancer originating from adenocarcinomas and submucosal tumors, such as lymphoma and gastrointestinal stromal tumors. Our patient had two distinct endoscopic findings that are different from those in previous reports. First, the surface of the mass was covered with normal mucosa, except for the ulcerated lesion. This finding differs from that of adenomas or adenocarcinomas. Second, colonic IPT with a pedunculated polyp is rare. In the literature review, only two cases had a pedunculated morphology. In our patient, the mucosal desquamation of the mass suggested a submucosal tumor, but the stalk of the mass suggested a malignant polyp originating from an adenocarcinoma.
Surgical resection is the most important treatment option. NSAIDs, chemotherapy, radiation treatment, steroids, and cyclosporin A have been used as treatment modalities, but the benefits are still unclear.
We reported an uncommon case of colonic IPT with pseudosarcomatous changes presenting as a large pedunculated polyp, mimicking a malignant polyp in the cecum, and reviewed the endoscopic findings of the cases reported in the literature. Correlations between endoscopic findings and colonoscopic biopsy are important for proper treatment because it is difficult to radiologically differentiate colonic IPT from other malignant tumors, and endoscopic resection is possible in cases of small tumors or those with pedunculated morphology.
The authors have no potential conflicts of interest.
None.
Conceptualization: HWK; Data curation: JSO, SBP, DHK, CWC, SJK, HSN, DGR; Writing–original draft: JSO; Writing–review & editing: all authors.
Abdominal computed tomography images. (A) A well-enhancing soft-tissue mass (blue arrow), measuring approximately 4 cm, at the ascending colon. (B) Increased colonic wall thickness (red arrow) of the ascending colon and cecum.
Colonoscopic findings. (A, B) An approximately 4–5 cm polypoid mass with a short stalk, thickly coated exudates, mucosal desquamation, and deep ulcers originating in the cecum.
Gross and pathologic findings. (A) A well-defined pedunculated mass at the cecum. (B) Ulceration (red arrow) with marked pleomorphic cell proliferation limited to the mucosa and submucosa (hematoxylin and eosin stain, ×6). (C) Marked pleomorphic cell (red arrows) and spindle cell proliferation (yellow arrows) with severe neutrophil infiltration (blue dotted arrows) (hematoxylin and eosin stain, ×200).
Characteristics summary and endoscopic findings of colon IPT patients reported in the PubMed database from 2000 to 2020
Case no. | Study | Sex/age (yr) | Location | Diameter (cm) | Endoscopic finding | Treatment |
---|---|---|---|---|---|---|
1 | Rosenbaum et al. (2000) |
M/73 | Sigmoid | 3.5 | Polypoid mass with nodular surfaces | Low anterior resection |
2 | Nakamura et al. (2010) |
F/82 | NA | NA | Multiple, small polyps with luminal stenosis | Observation and follow-up |
3 | Tanaka et al. (2010) |
M/79 | Ascending | 2 | Sessile mass with central depression | Rt. hemicolectomy |
4 | Tanaka et al. (2010) |
M/79 | Ascending | 2 | Polypoid mass with a short stalk | Rt. hemicolectomy |
5 | Jeong et al. (2011) |
F/30 | Splenic flexure | 5 | Polypoid mass with ulcers and a stalk | Lt. hemicolectomy |
6 | Salameh et al. (2011) |
M/2.6 | Sigmoid | NA | Polypoid mass covered with exudates | Lt. hemicolectomy |
7 | Kim et al. (2012) |
M/35 | Descending | 3.9 | Polypoid mass with shallow ulcers | Low anterior resection |
8 | Satahoo et al. (2013) |
M/14 | Rectum | 6 | Ulceroinfiltrative mass with luminal stenosis | Low anterior resection |
9 | Walia et al. (2014) |
F/10 | Ascending | 5 | Polypoid mass with shallow ulcers | Mid ascending colon segmental resection |
10 | Karaisli et al. (2020) |
M/42 | Cecum | 9 | Polypoid mass with nodular surfaces | Rt. hemicolectomy |
11 | Karaisli et al. (2020) |
M/40 | Descending | 6.5 | Polypoid mass | Lt. hemicolectomy |
IPT, inflammatory pseudotumor; M, male; F, female; NA, not available; Rt., right; Lt., left.