Primary Dedifferentiated Liposarcoma of the Colon - Report of a Rare Case with Review of Literature

Liposarcoma is the most common malignant soft tissue tumor in adults. Extremities and retroperitoneum are the common sites of involvement of liposarcoma. Liposarcoma of the gastrointestinal tract is rare and the colon is an extremely uncommon site. Mesenchymal tumors of the bowel are mainly represented by gastrointestinal stromal tumors (GIST). A sixty-one-year-old male patient presented with abdominal pain and distension. Contrast-enhanced computerized tomography (CECT) showed a circumferentially proliferative mass lesion in the mid ascending colon causing acute colonic obstruction with multiple large enhancing exophytic mass lesions of varying sizes on the peritoneal surface of the intestine. A right hemicolectomy was done. Gross examination showed polypoidal growth of 3.5x3x1.5 cm in the luminal aspect of ascending colon and a large exophytic firm mass in the transverse colon of 15x5.5x5 cm. There were multiple smaller exophytic nodules on the serosal aspect of the intestine. Microscopy showed neoplasm composed of atypical spindle cells in ill-defined fascicles and whorls. Foci showing aggregates of adipocytes of varying sizes with occasional lipoblasts were also noted. The spindly cells were Ckit negative, DOG 1 negative, and showed positivity for SMA. Based on morphology and immunoprofile, a diagnosis of dedifferentiated liposarcoma was given. This case represents dedifferentiated liposarcoma presenting as single endophytic and multiple exophytic masses and highlights the fact that, although rare, dedifferentiated liposarcoma can present as multiple intestinal mass lesions.