Occurrence of colonic liposarcoma after retroperitoneal liposarcoma

Liposarcoma, a neoplasm of mesen-chymal origin derived from adipose tissue, is one of the most common soft tissue sarcomas. Liposarcoma is usual-ly located in the lower limbs of adults, and retroperitoneal tumors are un-common [1]. It very rarely presents in the gastrointestinal tract and even less frequently in the colon [2]. Despite the potential involvement of the gastro-intestinal tract, the precise location of secondary colonic tumor development has not been described yet. Herein, we report a case of colonic liposarcoma in a patient who had previously been di-agnosed with retroperitoneal liposar-coma.A 73-year-old male presented with a 3-week history of abdominal pain. Fif-teen years prior, he had been diagnosed with liposarcoma in the retroperitone-al area adjacent to the right kidney. At that time, he underwent wide resec-tion of the mass, including a right ne-phrectomy. The retroperitoneal mass weighed 1,440 g and measured 23 × 15 × 7 cm in dimension at initial submis-sion. The external surface was lobu-lated and well-capsulated, and the cut surface revealed a highly myxoid ap-pearance with focal hemorrhages. The renal capsule of the right kidney was adhesive to the retroperitoneal mass, and tumor cells had infiltrated the per-irenal fat tissue; however, the kidney and renal pelvis were free from tumor extension. Tumor cells were mostly spindle cells, but occasional bizarre nuclei and very rare mitotic figures (less than 1/10 high power field) were also observed. The histological diag-nosis was a myxoid-type liposarcoma, and the tumor was determined to be of histological grade 1, according to the French Federation of Cancer Centers Sarcoma Group grading system (FN-CLCC). The patient received post-oper -ative radiotherapy (4,500 cGy) in the in-volved field. Surveillance checkups by computed tomography (CT) scan were performed over 9 years, with no conse-quent evidence of recurrence. The pa-tient did well for 15 years after the first operation. Clinical data were obtained from the patient’s hospital records and from communications with attending physicians.At the time of presentation with ab-dominal pain, physical examination on admission revealed a large, soft, ten-der mass, palpable in the right lower quadrant of the abdomen. A preoper-ative CT scan on admission showed a large, homogenous, smoothly outlined, low-attenuation tumor mass in the pelvis, close to the ascending colon (Fig. 1). Laboratory data on admission were unremarkable. Tumor markers including carcinoembryonic antigen, carbohydrate antigen 19-9 (CA 19-9), and CA-125 were within normal lim-