Retroperitoneal liposarcoma in an adult patient with Down syndrome.

Retroperitoneal liposarcoma is a rare solid tumour of mesenchymal origin with an incidence of 2.5 per million population. We report what is, to the best of our knowledge, the first case in the English literature of retroperitoneal liposarcoma in an adult patient with Down syndrome. The tumour was surgically resected with no use of adjuvant chemotherapy or radiation. No recurrence was found at follow-up 2 months postoperatively. Clinicians should consider retroperitoneal liposarcoma in the differential diagnosis of abdominal distention in adult patients with Down syndrome.