Retrorectal Myxoid Fibrosarcoma: A New Entity

A 40-year-old man was admitted to our department because of progressive increasing abdominal girth, asthenia and weight loss. On physical examination, the abdomen was distended owing to a huge, non-tender, palpable mass with no clear borders. Laboratory findings and tumor markers were within normal limits. A computed tomography scan revealed a bulky inhomogeneously enhancing retrorectal mass displacing completely the abdominal organs, with no clear signs of infiltration. T1and T2-weighted magnetic resonance imaging showed a well-defined soft-tissue mass measuring 24 × 17 × 9.0 cm located in retrorectal space (Figure 1). At laparotomy, a giant mixte tumor that filled completely the retrorectal space was found. The mass was totally excised and the main difficulty was to guarantee clear margins sparing the rectum and the sacrum (Figure 2). The rectum was spared and no intestinal resection was necessary to have clear margins. No lymph node dissection was done.