Large Colonic Lipoma Mimicking Colon Cancer and Causing Colonic Intussusception

Abstract

To the Editors:Large lipomas in the left colon are a rare entity, and those that are seen usually have a classic, benign appearance. We describe a patient with a large, left-sided, lipoma that mimicked an adenocarcinoma and produced a partial intussusception as well.A 69-year-old previously healthy man presented with a 1-month history of hematochezia and a 10-lb weight loss. The patient denied any changes in bowel movement frequency; he continued to average 1-2 bowel movements per day. He denied abdominal pain, nausea, or vomiting. Previous medical history included an appendectomy and hernia repair. The patient took no medications and denied any behavioral risk factors. Family history revealed a daughter with ulcerative colitis, and no colorectal cancer.Physical examination was unremarkable. The complete blood count and the basic metabolic panel were normal. Computed tomography (CT) revealed a mass in the descending colon, with partial intussusception involving the sigmoid colon, interpreted as a likely adenocarcinoma. There was no adenopathy or evidence of metastases. Colonoscopy revealed a 7-cm, ulcerated, fungating, mass on a thick stalk, with partial intussusception just distal to the splenic flexure ( Fig. 1). Biopsies of the mass only revealed benign inflammation without malignant tissue.Because of the appearance of the lesion and the negative findings of biopsies, a repeat colonoscopy was performed. After careful evaluation, the lesion was felt to be removable via endoscopic means alone. The lesion was removed with a large snare and electrocautery in a single piece. There were no complications. Pathology revealed a 7-cm inflamed and ulcerated lipoma, with no evidence of malignancy. The patient has done well thereafter.This case demonstrates how, on rare occasions, large colonic lipomas and malignancies can be difficult to differentiate prior to resection. With regards to symptoms and endoscopic appearance, the two can be indistinguishable. Even with abdominal imaging and direct colonoscopic visualization, lipomas can imitate carcinomas.Despite being the third most common benign tumor of the colon, colonic lipomas are comparatively rare [1], with a reported incidence less than 5% [2, 3]. Colonic lipomas are positively correlated with distance from the anus. Unlike that in our patient, almost half are found in the ascending colon [4].Colonic lipomas are most frequently small and asymptomatic [5]. Only one-quarter of all lipomas are symptomatic [6], and those symptomatic lipomas are generally larger than 2 cm, as was the case in our patient. Symptoms can include obstruction, bleeding, or, very rarely, intussusception, as was seen in our patient [2,3].With barium enema, lipomas most often appear as ovoid, well-demarcated, filling defects. By the application of external pressure to the abdomen, or with physiological peristalsis, a ''squeeze-sign''-a change in the appearance of the filling defect-can sometimes be elicited. On CT scan, lipomas also typically appear ovoid, with well-defined margins, and with absor...

Giant colon lipoma

“…They trigger symptoms once they reach large sizes, especially when they are larger than 2 cm (1, 2, 5, 7). Only 25% of them are symptomatic and the most frequent symptoms include abdominal pain, rectal bleeding and changes in bowel movements (1,2,4,9). Our patient presented with symptoms of colic-like abdominal pain and abdominal distension.…”

“…Typically, cushion sign (a cushion-like collapse once the biopsy forceps is pressed down), tent sign (a tent-like appearance once the covering mucosa is lifted with a forceps) and exposed fat sign (yellowish fat exposed at the biopsy site) may be seen (1,2,9). In that respect, colonoscopy is reliable for the diagnosis of classical lipomas; however, diagnosis is difficult in cases of atypical callous or ulcerated lesions (2, 7).…”

Giant Submucosal Lipomatous Polyp Causing Perforation of Sigmoid Colon: A Case Report and Review of Literature

“…Sarcomatous changes in these colonic lipomas have been reported only in a few cases [9]. Intermittent torsion and ischemia can give rise to an ulcerated fungating mass that may give a pseudomalignant appearance on colonoscopy [10]. The greatest clinical significance of submucosal lipomas lies in their potential to be confused with adenomatous polyps or other aggressive pathology [11].…”

Giant Intraperitoneal Lipoma of the Cecum

“…13 Large colonic lipomas, can sometimes be mistaken for malignancy, which may result in extensive surgical operations. 3 Surgical resection is recommended for larger lipomas to relieve the symptoms or exclude malignancy. 14 If the preoperative diagnosis of colonic lipoma can be made correctly, the extent of surgery may be appropriately limited.…”

“…2 Large colonic lipomas can be mistaken as malignancy, which may result in extensive surgical operations. 3 Various surgical treatment options can be taken in to account in colonic lipomas. Hereby we intended to present a case of a 13 cm giant cecal lipoma treated by laparatomy and excision in a 64 year old man suffering from abdominal pain.…”