LAUSR

A 72-year-old woman presented with a pancreatic mass which was found incidentally on abdominal ultrasound for health checkup. Her medical history was noted for systemic arterial hypertension, diabetes mellitus, and coronary heart disease. Physical examination was unremarkable. All results of her hematologic and biochemical tests were within the normal limits, including routine blood tests, serum lipase levels, hepatic functions, and carcinoembryonic antigen. Abdominal computed tomography scan revealed a mass measuring 9.7 × 5.1 × 4.5 cm in the pancreatic body and tail (Fig. 1a). The mass had a heterogeneous appearance, but most areas of the mass were of low density consistent with cutaneous fat, which was mildly enhanced after contrast injection as shown on the coronal scans (Fig. 1b). At laparotomy, the patient had a primary tumor measuring 10.3 × 5.2 × 4.8 cm in the distal body and tail of the pancreas attached to the spleen and left adrenal gland. She underwent distal pancreatectomy with splenectomy and adrenalectomy. The operative specimen was yellow, soft, elastic, and lobulated, resembling adipose tissue on the cut surface (Fig. 2). Histopathologically, the neoplasm predominantly consisted of mature-looking fat tissue, which showed variable size and shape variation of adipocytic element with the presence of numerous multivacuolated lipoblasts. Final diagnosis of well-differentiated liposarcoma was established. Her postoperative recovery was uneventful, and the patient was under surveillance without additional treatment. Liposarcoma represents one of the most common malignant mesenchymal tumors in adult population and usually occurs in the retroperitoneum and deep soft tissues of the trunk and lower extremities. As one of retroperitoneal organs, pancreas is an extremely rare site of primary liposarcoma. The etiology of pancreatic liposarcoma is unknown, although trauma or radiation exposure has been suggested. Liposarcomas may appear at any life expectancy, but most occur at 40–60 years of age. The patients usually present abdominal symptoms like pain and distension, and occasionally, systemic symptoms may occur, like anorexia and weight loss. Exceptionally, patient is asymptomatic, as described in our patient. There are no reports of increased tumoral markers by date. Magnetic resonance imaging or computed tomography scan is of great importance for evaluating the lesions, not only in recognizing the tumor but also in calculating the fat component of the tumor, depicting better characterization of the mass: 100% fat content is in fact consistent with a lipoma, whereas < 75% signifies atypical lipomas or low-grade sarcoma. The differential diagnosis on imaging may need to include focal fatty infiltration, lipoma, teratoma, lipomatous pseudohypertrophy, mesenteric panniculitis, and angiomyolipoma, similar to our patient. Only a limited number of cases have been reported about primary pancreatic liposarcoma, so the prevalence and survival rate are still unknown. Surgical resection is currently the only potentially curative therapy for liposarcomas in general. Because of frequent local recurrence of liposarcomas of other organs, regular follow-up should be recommended in those patients even with complete excision of pancreatic liposarcoma.