Giant Submucosal Colonic Lipomata: Report of a case and review of the literature.

Dr David A. Montgomery

Mr John Reidy

Department of Surgery, Inverclyde Royal Hospital, Larkfield Road, Greenock, PA16 0XN

 SMJ 2004 49(2): 71

 

Abstract

Giant submucosal colonic lipomas are an uncommon cause of colonic symptoms.  There is great debate in the literature as to how best to deal with these.  We present a patient with a large colonic lipoma causing abdominal pain and altered bowel habit.  It was successfully treated by open colostomy and resection.

 

Key Words: submucosal, colonic, lipoma, mesenchymal, neoplasms, tumours.

 

Introduction

Colonic lipomas are benign tumours arising from adipose connective tissue in the bowel wall.  The first description is attributed to Bauer in 1757.  They are commonly described as a rare colonic tumour1,2, but are in fact the most common benign mesenchymal tumour found in the colon3, and the second most common benign colonic polyp after adenomatous polyps4.  Colonoscopy studies put the incidence at between 0.11% and 0.15%5,6, while autopsy studies estimate prevalence at anywhere between 0.2% and 4.4% of people7.  Estimating frequency is difficult, as most are small and asymptomatic8.  One review suggests an average size of 4.4 x 3.1 x 2.7 cm9.

 

Although uncommon, large colonic lipomas merit attention, as they are often symptomatic and may be mistaken for malignancy9,10.

 

Case Report

We report a case of a 73-year-old lady who presented to her GP with a long history of altered bowel habit.  She had been suffering alternating periods of constipation and diarrhoea since undergoing cholecystectomy for gallstone disease in 1994. In addition, in the six months prior to visiting her GP she noticed increasing abdominal pain.  The pain was mainly in the right upper quadrant, radiating down the right side.  It was “gripping” in nature, and episodes of pain were usually followed by passage of loose stool.  At the time of presentation to her GP, the patient was experiencing episodes of pain every day and had suffered several episodes of faecal incontinence.  There had been no mucus or blood passed per rectum, and no weight loss.

 

Colonoscopy revealed a large mobile lesion in her colon arising from near the hepatic flexure.  Surface biopsies revealed normal colonic mucosa.  Barium enema showed the lesion to be a mobile mass 15 cm long by 4 cm in diameter arising from a point of fixation on the lateral border of the upper ascending colon and lying in the descending colon and caecum.  Barium flowed freely to the ceacum.  CT one month later revealed the lesion was now lying along the transverse colon, filling 50% of the lumen.  CT density of the lesion suggested it was lipomatous.  A diagnosis of mobile submucosal colonic lipoma was made.  The lesion was not thought to be responsible for our patients symptoms, and a period of observation was undertaken.

 

Worsening of symptoms prompted a repeat CT 6 months later.  The appearances were unchanged.  At this point, she was referred for a surgical opinion.  She was taken to theatre on an elective basis and laparotomy was carried out.  Colotomy was performed and the lesion was excised.  Excision resulted in a small defect in the muscle layer of the colon, and this was oversown.

 

Fig 1: Lipoma in situ

The pathology report of the specimen confirmed it to be a submucosal lipoma, 8cm long by 3cm in diameter.  The patient was followed up at clinic at six weeks and was pain free with normal bowel motions.

 

Review of the Literature

Autopsy studies reveal colonic lipomas to be more common in women (56%) than men (44%)7,9.  They occur in older patients (average age 60)9.  70% are localized to the right hemi-colon; the caecum, ascending and transverse colon in descending order of frequency10.  Men have a slight increased propensity towards left sided lesions10.  Pathologically, these tumours are well differentiated and arise from adipose connective tissue in the bowel wall.  90% are submucosal in origin.  The rest are either subserosal (more common) or intramuscular mural9,10.

 

Colonic lipomas are commonly small and asymptomatic.  Symptoms, when present, vary according to site of the lipoma.  Abdominal pain (23%) and rectal bleeding due to ulceration of overlying mucosa (20%) are most common, with other symptoms such as anaemia, weight loss, nausea, vomiting and abdominal distension reported less frequently9.  Abdominal pain can be attributed to several causes.  These include obstruction, particularly in the relatively rare rectal lipomas, and intermittent intussusception, of which lipomata are the most frequent cause in adults9.  Other dramatic presentations include perforation and appendicitis due to appendiceal obstruction.

 

Diagnosis can be difficult. However, pre-operative diagnosis is important as these lesions present in a similar age group and with similar symptoms as do colonic malignancies.

 

Pre-operative diagnosis has been claimed by some authors to be possible in around 60% of cases.  It depends on a number of features being present.  The “squeeze” sign is seen radiographically and describes elongation of a radio-opaque filling defect during peristalsis.  Lipomas can be directly visualized during colonoscopy and biopsies taken.  Lipomas are covered by normal mucosa, and specimens will reflect this.  Normal mucosa on biopsy does not rule out malignant connective tissue tumours, but is relatively re-assuring for the lack of malignancy.  Other features on colonoscopy include the “tenting” sign, where the mucosa tents over the lesion when grasped with forceps, the “cushion” sign, where flattening of the lesion is followed by restoration of its shape on pressure being removed, and the “naked fat” sign, where adipose tissue discharges from the mucosal defect following biopsy7, 11-13.  CT and MRI may also have a role to play, but diagnosis is commonly confirmed only after excision of the lesion.

 

The vast majority of colonic lipomata are found incidentally.  Asymptomatic lesions should be left.  Larger lesions will often need resected, either due to symptoms or uncertainty over diagnosis.  There is currently no consensus over how to proceed in this regard. 

 

Several studies report safe endoscopic removal of colonic lipomas14,15,16.  However, removal of lesions greater than 2 cm has been associated with a higher risk of perforation14.  Pfeil et al, in a series of 7 patients, reported a 42.8% rate of perforation in lipomas resected endoscopically16.  Risk factors for perforation were a broad base and a high volume on histopathology.  In all three cases complicated by perforation, smooth muscle from the muscularis propria was identified in the specimen, and one specimen contained serosa16. Other authors report similar problems9, and muscularis was noted in our specimen.  The risk of perforation has led numerous authors to advocate open surgery as the resection method of choice7,11. 

 

More recently, several authors have proposed methods of ensuring safe endoscopic removal colonic lipomas.  Saline injection to the base has been proposed17, and this is associated with reduced risk of perforation by reducing the likelihood of ensnaring underlying muscularis during resection.  Kim et al additionally utilised endoscopic ultrasound to evaluate the deep margins of 4 colonic lipomas.  In all four cases, the lesion displayed endoscopic features typical of a lipoma, and ultrasound revealed no extension into the underlying muscularis.  The base was then injected with either saline or a solution of 1:10,000 epinephrine (5-10ml) to raise the lesion.  Endoscopic removal was then carried out safely14.

 

Summary

Colonic lipomas are not common, but do occur in clinical practice.  They are usually found incidentally and require no intervention.  Occasionally, they cause symptoms and require resection.  Numerous diagnostic methods are available, but no method is definitive.  If doubt exists about the nature of a colonic lesion, resection should be undertaken.

 

The literature supports the contention that removal of lesions under 2cm in size by colonoscopic means is safe.  These lesions are rarely symptomatic, however, and most would suggest that they can be observed.  Symptomatic lesions are usually larger than 2cm.  There is no consensus over the correct management of larger lesions.

 

Various techniques are described in the literature to maximise the safety of endoscopic removal of colonic lipomas.  However, the majority of clinicians practicing in Britain will not have access to endoscopic ultrasound to enable the full assessment of these lesions.  Injection polypectomy does reduce the risk of perforation, but will not eliminate it for the 10% of lipomas which arise from the muscularis.  It is the contention of this author that, In the absence of endoscopic ultrasound, large symptomatic colonic lipomas would be more safely resected at open surgery.

 

References

  1. Bala D. Czechowicz W.  Sir J.  The case of a giant lipoma polyp in transverse colon.  Acta Endoscopica Polona 2000;10:89-91.

  2. Kurosaki T. Fujikawa T. Katayama R. Ikeuchi K. Takao Y. Ootsuka M. Anazawa S.  A case of giant lipoma of colon.  J. Japan Soc. Colo-Proct. 1996;49:373-377.

  3. Cossavella D. Clerico G. Rosato L. Galetto PV. Paino O. Trompetto M. Realis Luc A. Pozzo M.  Colonic lipoma: An unusual case of recurrent intestinal obstruction.  Clinical case and survey of the literature.  Minerva Chirurgica 1998; 53:277-280.

  4. Rogy M. Mirza D. Berlakovich G. Winkelbauer F. Rauhs R. Submucous large bowel lipomas – presentation and management.  Eur J Surg 1991;157:51-57.

  5. Ivaldi L. Carozza V. Perino M. Gambetta G. Mura G. Bianco A. Revetria P. Large Bowel Lipomas.  Chirurgia 2001;14:155-156.

  6. Chung YFA. Ho Y-H. Nyam DCNK. Leong AFPK. Seow-Choen F. Management of colonic lipomas.  Aust N Z J Surg 1998;68:133-135.

  7. Vecchio R. Ferrara M. Mosca F. Ignoto A. Latteri F. Lipomas of the large bowel.  Eur J Surg  1996;162:915-919.

  8. Bombi JA.  Polyps of the colon in Barcelona, Spain.  An autopsy study.  Cancer 1998;62:1472-1476.

  9. Franc-Law JM. Begin L. Vasilevsky C-A. Gordon PH.  The dramatic presentation of colonic lipomata: Report of two cases and review of the literature.  Am Surg 2001;67:491-494.

  10. Bardaji M. Roset F. Camps R. Sant F. Fernandez-Layos MJ.  Symptomatic colonic lipoma: Differential diagnosis of large bowel tumours.  Int J. Colorect. Dis. 1998;13:1-2.

  11. Taylor B. Wolff B. Colonic lipomas. Report of two unusual cases and review of the Mayo Clinic experience 1976-1985.  Dis Colon Rectum 1987;30: 888-893.

  12. Michowitz M. Lazbuik N. Noy S. Nazbuik R. Lipoma of the colon, a report of 22 cases.  Am Surg 1985;51:494-495.

  13. Castro E. Stearns M. Lipoma of the colon, a review of 45 cases. Dis Colon Rectum 1972;15:441-444.

  14. Kim CY, Bandres D. Lok Tio T. Benjamin SB. Al-Kawas FH. Endoscopic removal of large colonic lipomas.  Gastrointest Endosc 1991;55:929-931.

  15. Saclarides T. Ko S. Airan M. Dillon C. Franklin J. Laparoscopic removal of a large colonic lipoma. Report of a case. Dis Colon Rectum 1991;34:1027-1029.

  16. Pfeil SA. Weaver MG. Abdul-Karim FW. Yang P.  Colonic lipomas: outcome of endoscopic removal. Gastrointest Endosc 1990;36:435-438

  17. Wave JD. Saline injected colonoscopic polypectomy (editorial). Am J Gastroenterol. 1994:89;305-306

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