Endoscopically Removed Giant Submucosal Lipoma Veliki Submukozni Lipom Endoskopski Uklonjen

Background. Although uncommon, giant submucosal colon lipomas merit attention as they are often presented with dramatic clinical features such as bleeding, acute bowel obstruction , perforation and sometimes may be mistaken for malig-nancy. There is a great debate in the literature as to how to treat them. Case report. A patient, 67-year old, was admitted to the Clinic due to a constipation over the last several months, increasing abdominal pain mainly localized in the left lower quadrant accompanied by nausea, vomiting and abdominal distension. Physical examination was unremarkable and the results of the detailed laboratory tests and carcino-embryonic antigen remained within normal limits. Colonos-copy revealed a large 10 cm long, and 4 to 5 cm in diameter, mobile lesion in his sigmoid colon. Conventional endoscopic ultrasound revealed 5 cm hyperechoic lesion of the colonic wall. Twenty MHz mini-probe examination showed that le-sion was limited to the submucosa. Since polyp appeared too large for a single transaction, it was removed piecemeal. Once the largest portion of the polyp has been resected, it was relatively easy to place the opened snare loop around portions of the residual polyp. Endoscopic resection was carried out safely without complications. Histological examination revealed the common typical histological features of lipoma elsewhere. The patient remained stable and eventually discharged home. Four weeks later he suffered no recurrent symptoms. Conclusion. Colonic lipomas can be endoscopi-cally removed safely eliminating unnecessary surgery.


Introduction
Colon lipomas are benign tumors arising from adipose connective tissue in the bowel wall.They are often described as rare colonic tumors 1−4 , but it is difficult to estimate the true frequency, as most are small and asymptomatic or mildly symptomatic 5 .Colonoscopy studies revealed incidence between 0.11 and 0.15% 6,7 , while autopsy studies es-timate the prevalence between 0.2 and 4.4% of people 8 .Although uncommon, large colonic lipomas merit attention as they are often presented with dramatic clinical features such as bleeding or acute bowel obstruction and sometimes may be mistaken for malignancy 9,10 .We report a case of large, submucous sigmoid colon lipoma and review the literature to evaluate the clinical features, diagnosis and treatment of this disease.

Case report
We report a case of 67-year-old man who presented to his general practitioner (GP) with a history of altered bowel habit.He had been suffering from constipation over the last several months.In addition, several weeks prior to visiting his GP he started feeling increasing abdominal pain.The pain was mainly localized in the left lower quadrant.At the time of presentation to his GP the patient was experiencing episodes of pain every day accompanied by nausea, vomiting and abdominal distention.He had no history of mucus or blood passed per rectum, and no weight loss.Physical examination was unremarkable and the results of the detail laboratory tests including complete blood cell counts, blood biochemistry and carcinoembryonic antigen remain within normal limits.He was referred to our institution for further investigation.Colonoscopy revealed a large, yellowish, 10 cm long by 4 to 5 cm in diameter, mobile lesion in his sygmoid colon (Figure 1).The overlying mucosa was smooth, and the lesion was soft, compressible ("cushion" or "pillow" sign) with "tenting" sign of the mucosa when grasped with forceps.Surface biopsies examination revealed normal colonic mucosa.A diagnosis of mobile submucosal colonic lipoma, was considered as the most probable but malignancy could not be excluded.

Fig. 1 − Large 10 cm long by 4 to 5 cm in diameter, mobile lesion in sygmoid colon with macroscopically intact overlaying mucosa
Conventional 7.5 and 12 MHz endoscopic ultrasound (EUS) revealed 5 cm hyperechoic lesion of the colonic wall (intramural lesion).Twenty MHz mini-probe examination further showed (intramural) infiltration of the colonic wall limited to the submucosa and no extension to underlying muscularis propria was noted (Figure 2).The hyperechoic pattern of the lesion at EUS was consistant with a lipoma lying within the submucosa.Initially, the base of the polyp was injected with a solution of 1 : 10 000 epinephrine (8 ml) to elevate the lesions.Since polyp appeared too large for a single transaction, it was removed piecemeal with standard rotable oval type electrosurgical snare.Although largest portion of the polyp was snared and continuous current was ap-plied along with wire retraction, because snare handle was at the end of its travel and polyp had not been transected, cutting current had to be used to sever the reminder of the lesion.Once the largest portion of the polyp has been resected, it was relatively easy to place the opened snare loop around portions of the residual polyp.Endoscopic resection was carried out safely without complications.Gross finding of polypoid formation depicted lipomatous expansion of the submucosal layer.Histological examination revealed the common typical histological features of lipoma elsewhere.Submucosal overgrowth of lobulated mature fat tissue protuberated and was covered with the raised histologically regular colonic mucosa (Figure 3).The patient remained stable and eventually discharged home.An office visit four weeks later failed to reveal any recurrent symptoms.He was pain-free with normal bowel motions.

Discussion
Lipomas are the most common nonepithelial tumors of the gastrointestinal tract 4 .In the colon, however, lipomas are uncommon.They occur in older patients (average age, 60 years) 4,5,10 .Seventy percent are localized in the right hemi-colon.These tumors are well differentiated and most frequently arise from adipose tissue in the bowel wall.They are usually (90%) submucosal in origin.The rest are either subserosal (more common) or intramuscular mural 4,5,9,10 .Colonic lipomas rarely cause symptoms 11 and among the most common problems when they occur are bleeding 12 , obstruction 13 , perforation and intussusception 14,15 .
Diagnosis can be difficult.Pre-treatment diagnosis is important as these lesions present in a similar age group and with similar symptoms as do colonic malignancies.Lipomas can be directly visualized during colonoscopy and biopsy taken.Normal mucosa on biopsy is relatively re-assuring for the lack of malignancy.
Symptomatic lipomas need resection, and there is currently no consensus on treatment of these lesions.Several studies report successful endoscopic resection of submucosal colonic lesions including lipomas 16−18 .Removal of lesions greater then 2 cm has been associated with higher risk of perforation 16,19,20 and Pfeil et al. 17 in their series reported the rate of perforation as high as 43% in lipomas resected endoscopically.Interestingly, in all three cases complicated by perforation, smooth muscle from the muscularis propria was identified in the specimen, and one specimen contained serosa 17 .As it was described recently, endoscopic ultrasound can be used to evaluate the depth of colonic lipoma margins and to distinct the origin of the lipoma in the bowel wall further ensuring safe endoscopic removal 16, 21−23 .In our case, lesion displayed echosonographic features typical of a lipoma and revealed no extension into the underlying muscle.The base was then injected with a solution of 1 : 10 000 epinephrine (8 ml) to elevate the lesions and endoscopic removal was carried out safely.
Colonic lipomas are rare in clinical practice and they occasionally require resection due the symptoms they cause.The literature supports the concept of endoscopic resection for the lesions less then 2 cm in diameter if they are symptomatic.But, since these lesions are rarely symptomatic, the most would suggest observation and follow-up 4, 6, 7, 16−20 .

Conclusion
Currently, the indication for endoscopic resection of symptomatic, larger then 2 cm colonic lipoma is still a controversial subject.In our opinion, endoscopic therapy is enhanced in the presence of endoscopic ultrasound and the risk of perforation can be reduced further for those 10% lipomas which arise from the muscle, which would be more safely resected at open surgery.Lipomas are benign tumors; and if a lesion is found, minimally invasive endoscopic procedures should be selected as colonic lipomas can be removed safely following the guidance of the presented therapeutic strategy eliminating unnecessary surgery.