gastrointestinal lipomas are rare , mostly small and detected incidentally during endoscopic examination ( 1 ) .
these tumours are benign proliferations of mature fatty tissue arising in the submucosa and predominately arise in the large intestine ( 51 - 70% ) preferentially on the right side .
the majority of symptomatic lesions occur in adults in the sixth decade of life ( 2 ) .
lipohypertrophy of the ileo - caecal valve is classified as a variant of normal ( 1 ) . the vast majority are asymptomatic but they can manifest due to intussusceptions , ulceration leading to haemorrhage or iron deficiency anaemia , intestinal obstruction or present as an abdominal mass . most are compressible and submucosal although they can rarely develop in the serosa and appear as a fold or polyp .
they contain mature adipose tissue and usually have a thick capsule surrounding the tumour ( 2 ) .
these changes if extensive can mimic a liposarcoma ; however , frank liposarcoma of the colon is extremely rare and requires the presence of lipoblasts ( 2 ) .
mucosal biopsies can be unhelpful and yield either intact mucosa , granulation / inflammatory changes or fat necrosis .
. it can be difficult to separate the two and even endoscopic ultrasound can be non - diagnostic and adequate histology sampling may require a resection ( 3 ) . where a biopsy diagnosis has been made endoscopic resection or limited resection can be undertaken removing the need for major resectional surgery ( 3 ) .
where this is not technically feasible a minimally invasive approach using either mini - laparotomy or laparoscopic resection has successfully been reported ( 4,5 ) .
a 74 year old man with a background of chronic obstructive airways disease ( coad ) was referred for urgent assessment by his general practioner with a 1 month history of lower abdominal pain and altered bowel habit .
abdominal and rectal examination was unremarkable and routine blood testing including carcinoembryonic antigen ( cea ) was normal .
a large ulcerating polypoidal lesion was found at his hepatic flexure ( figure 1 ) .
colonoscopy demonstrating large pedunculated ulcerating lesion found at hepatic flexure histology from biopsies taken showed no evidence of neoplasia or dysplasia but was felt to most likely be unrepresentative of the endoscopic lesion .
a staging ct scan of chest , abdomen and pelvis was arranged as part of pre - operative staging protocol and this demonstrated a large 3.3 x 4.3 x 3.4 cm heterogeneous enhancing colonic polyp , which predominately enhanced with fatty attenuation ( figure 2 ) .
proximal to the lesion was circumferential colonic wall thickening and surrounding fat stranding suspicious of colonic malignancy .
there was concern about colonic malignancy and following discussion at a mdt meeting he was offered a surgical resection .
ct scan of the abdomen showing the lesion ( marked a ) a laparoscopic extended right hemicolectomy was performed under general anaesthesia .
there were no complications and the patient made an excellent recovery and was discharged home .
gross and microscopic histological examination showed a submucosal lipoma with areas of fat necrosis and surface ulceration with extensive granulation tissue .
polypoidal tumour measuring 4 cm with an area of central ulceration gross slices of the tumour show adipose tissue expanding the submucosa .
there are areas of fat necrosis and mucosal ulceration microscopy shows lobules of mature adipocytes .
imaging may reveal tissue with the signal and uptake of adipose tissue but a confident diagnosis may not be possible .
endoscopists , radiologists and pathologists need to be aware of this entity . careful discussion and review of the investigations at an mdt meeting may permit a pre - operative diagnosis .
endoscopic resection can be used where technically feasible but where doubt remains or this is not feasible then laparoscopic or open resection may be required .
 lipomas of the alimentary tract are rare tumours that can mimic malignant lesions . 
 they are often small and asymptomatic although larger tumours can present with intusussception or as abdominal masses . 
 we present a case of a transverse colon submucosal lipoma masquerading as a colonic adenocarcinoma leading to resection.a 74 year - old - man was referred urgently for assessment with altered bowel habits , and lower abdominal discomfort along with a positive faecal - occult - blood sample . 
 colonoscopy demonstrated a large polypoidal lesion at the hepatic flexure with ulceration . 
 biopsies were inconclusive . a staging ct scan confirmed a 3.3 x 4.3 x 3.4 cm polyp with colonic wall thickening suspicious of malignancy . 
 an extended right hemi - colectomy was performed . 
 histology showed a large submucosal lipoma with 12 reactive lymph nodes.colonic lipoma often present as incidental findings detected on either imaging or endoscopically whilst investigating other symptoms . 
 their appearances can mimic colonic malignancy and surgical resection may be required . 
INTRODUCTION
CASE REPORT
DISCUSSION