Lipoma of the transverse colon covered by tubulovillous adenoma: a rare indication for surgical treatment

Intestinal "Piggybacking Lipoma", A Unique Lipoma Composed of Lipoma and Overlying Epithelial Lesions: A Case-control Study and Review of Literature

BACKGROUND/AIM

Lipomas are rare but the most common benign mesenchymal lesions of the gastrointestinal (GI) tract, composed of mature adipose cells. The "piggybacking lipoma" is formed by lipomas with overlying polypoid epithelial lesions, such as sessile serrated lesion, tubular adenoma, or hyperplastic polyp, and the literature on these lesions is limited. In this study, we systematically investigated the clinical, endoscopic, and pathologic characteristics of these unique lipomas.

PATIENTS AND METHODS

This is a single-institution retrospective study of gastrointestinal tract lipomas diagnosed from 2016-2021. Those with concurrent polypoid epithelial or mesenchymal lesions during the same endoscopic episode were included and reviewed in this study, and the lipomas were classified as "piggybacking lipoma" or "non-piggybacking lipoma" depending on whether the concurrent lesion was overlying the lipoma or was at a different location in the intestine. Demographic, clinical, and endoscopic data were obtained from electronic medical records.

RESULTS

A total of 100 lipomas with concurrent epithelial or mesenchymal lesions were included in this study. Among them, 21 cases were classified as "piggybacking lipoma" and 79 were classified as "non-piggybacking lipoma". Patients with piggybacking lipomas showed a female predilection, and were more likely to be symptomatic and less likely to exhibit classic endoscopic features of lipoma. Histologically, the piggybacking polyps showed overlying sessile serrated lesions (SSL) (76.2%) and tubular adenoma (TA) (19%), whereas the non-piggybacking group had differing characteristic lesions with TA (57.5%) and SSL (6.0%).

CONCLUSION

Piggybacking lipomas are rare lipomas with overlying polypoid epithelial lesions, most commonly SSL. They present different clinical, endoscopic, and pathologic features compared to non-piggybacking lipomas.

Large colonic lipoma with a laterally spreading tumor treated by endoscopic submucosal dissection: A case report

BACKGROUND

Since fat does not transmit electrical energy well, delayed perforation and post-polypectomy syndrome due to electrical thermal injury are concerns in the endoscopic removal of colonic lipoma. The endoscopic submucosal dissection (ESD) technique concentrates electrical energy conducts to the submucosa, not the adipose tissue. This helps to minimize electrical thermal injury, especially in the case of large colonic lipomas. In rare cases, such as colonic lipomas accompanied by mucosal lesions, it is difficult for endoscopists to decide how to safely remove them.

CASE SUMMARY

A 78-year-old man underwent colonoscopy for colorectal cancer screening. During colonoscopy, a yellowish submucosal tumor with positive cushion sign was observed in the ascending colon measuring about 4.5 cm. A nodular mucosal lesion of about 2.5 cm was observed on the mucosal surface of the lipoma. The lipoma was so large that it occupied much of the inside of the colon, making it difficult to see the entire laterally spreading tumor (LST) at once. The LST was confined to the surface of the lipoma, which had a semipedunculated shape with a wide neck. The margin of the LST was not observed at the neck of the lipoma. ESD was performed and the colonic lipoma with the LST was successfully removed without complications. After 3 d of hospitalization, the patient was discharged without any symptoms. The final pathology report showed that the lesion consisted of submucosal lipoma and tubulovillous adenoma with low-grade dysplasia.

CONCLUSION

ESD is effective and safe for treating a large colonic lipoma with an LST by minimizing electrical thermal injury.

Management Options of Giant Colonic Lipomas

Colonic lipomas are rare, benign neoplasms, typically asymptomatic, and predominantly found incidentally during autopsy or routine surveillance. Symptomatic lesions are usually those greater than 2 cm in diameter while “giant” lesions are characterized as those over 4 cm. Presentations can vary from asymptomatic to more severe sequelae, including obstruction, gastrointestinal bleeding, or intussusception. Resection of these lesions has historically been restricted to large or symptomatic lesions. However, recent reports suggest lipomas may retain the ability to grow and can become symptomatic over time despite being inconsequential initially. This series provides a review of the clinical manifestations of colonic lipomas, radiographic characteristics, and a treatment recommendation for management of these lesions using minimally invasive surgical techniques whilst advocating for consideration of resection prior to the development of symptoms or more emergent complications.