Pedunculated colonic liposarcoma of the ileocecal valve manifesting as intussusception: A case report and literature review

To the Editor, Liposarcoma generally arises from the soft tissue of the retroperitoneum and extremities. The development of a primary liposarcoma in the gastrointestinal tract is rare. Few cases of primary colonic liposarcoma have been reported, and peduncular colonic liposarcomas are especially rare. Only one case of liposarcoma arising at the ileocecal valve has been reported. Due to its rarity the clinicopathological behavior, optimal treatment and prognosis of liposarcoma remain unclear. Here we described the development of an intraluminal colonic liposarcoma that caused ileocolic intussusception, leading to the administration of ileocecectomy. A 59-year-old man had a 3-cm mass arising from the ileocecal valve during a colonoscopy which was performed at a local clinic 9 years previously (Figure 1A), with biopsy-confirmed histopathology stating non-specific chronic inflammation. He was subsequently followed up annually with a surveillance colonoscopy at the same clinic, with no pathological examination performed. The patient first visited the National Cancer Center of Korea in 2014, when a fatty mass of approximately 3.7 cm in diameter was observed at the ileocecal valve on a computed tomography (CT). No specific findings were detected on a chest CT. Esophagogastroduodenoscopy was performed during his follow-up at our center, and there were no specific findings other than scarring from a duodenal ulcer. He was diagnosed with lipoma and followed up regularly. In 2019, a biopsy was performed as some necrotic changes and focal active inflammation, along with inflamed granulation tissue formation, were identified on endoscopy. When he was re-examined after 6 months, the size of the lesion had increased (Figure 1B) and endoscopic resection was attempted. Subsequently, surgical resection was planned due to the failure of the endoscopic procedure. However, before the scheduled date of surgery the patient was admitted to the emergency room due to abdominal pain. On the abdominal CT scan, a fatty mass measuring approximately 10.5 cm 3.8 cm at the ileocecal valve was confirmed, resulted in ileocolic intussusception (Figure 1C). No lymph node or distant metastasis was noted. The patient underwent a laparoscopic ileocolic resection one day after admission. Ileocolic intussusception was confirmed during laparoscopic exploration, but there was no evidence of inflammation or infiltration around the lesion. The peritoneum was incised along the base of the ileal mesentery upward to the duodenum to expose the cecum and terminal ileum. A tunnel was created in the retroperitoneum to separate the ileal mesentery and mesentery of the ascending colon from the retroperitoneal structures. The ileocolic lymphovascular pedicle was isolated at its origin and ligated. The mesentery of the ileum was transected under application of triangulating tension. A transection of the mesocolon was completed up to the middle portion of the ascending colon. The specimen was pulled out through an extended port site on the infra-umbilical area (Figure 2). After resection of the terminal ileum and cecum, including part of the ascending colon, an end-to-end hand-sewn ileocolic anastomosis was performed and the mesenteric defect was closed. The bowel was carefully returned to the abdominal cavity. On gross examination of the specimen, a well-defined, multilobulated and pedunculated mass of 12.5 cm 4.5 cm 4.0 cm in size was observed at the ileocecal valve (Figure 3A). A cross-section of the lesion revealed a light-yellow and grayish-white heterogeneous lipogenic surface with multifocal hemorrhage and fibrosis (Figure 3B). The proximal and distal resection margins were 5.0 cm and 10.0 cm, respectively, free from tumor involvement. A histopathological examination revealed an atypical lipomatous tumor, suggestive of well-differentiated liposarcoma. The tumor extended into the muscularis propria. Mitosis was less than 1 per 10 high-power field (HPF), and mild nuclear pleomorphism was identified. Submucosal adipocytic proliferation and variable-sized adipose cells were observed (Figure 4A). Atypical spindle cells and lipoblastic cells were also observed (Figure 4B). No angiolymphatic invasion was identified. Immunohistochemistry revealed that 3% of tumor cells were positive for Ki-67 (Figure 4C), along with the presence of S-100 protein in lipoblasts (Figure 4D). No other specific findings were observed in the terminal ileum, cecum and appendix. The patient was discharged without immediate complications and no evidence of disease recurrence was found during the 18-month follow-up. Liposarcoma, a malignancy of the adipose cells, is the most common soft tissue sarcoma that occurs mainly in the extremities and retroperitoneum. Liposarcoma arising from the gastrointestinal tract, in particular the colon, is rare. Few cases have been reported in the literature. Table 1 summarizes 24 published cases of colonic liposarcoma. Median age of the patients was 57.5 years (range 3284 y), and four patients at the age of over 70 years had the pleomorphic or dedifferentiated subtype. Clinically, most patients presented Received: 28 April 2021 Revised: 19 August 2021 Accepted: 4 October 2021