CASE PRESENTATION: A 59-year-old female was referred to our hospital with a chief complaint of right lower quadrant
abdominal pain. Abdominal computed tomography revealed a large retroperitoneal
tumor with a maximum diameter of 11 cm. The
tumor involved retroperitoneal major vasculatures, such as the right common iliac vein and artery, as well as the right psoas muscle and femoral nerve. The right ureter was also involved and obstructed by the
tumor. A biopsy was performed through the retroperitoneal route, and the
tumor was diagnosed as a
dedifferentiated liposarcoma with the Fédération Nationale des Centres de Lutte Contre le
Cancer grade 3. Because the
tumor was highly invasive and complete resection was not feasible, we decided to administer
neoadjuvant chemotherapy with
doxorubicin and
ifosfamide (AI). After completing 6 courses of AI, the
tumor size was considerably reduced, and we decided to perform surgery with curative intent. Before
laparotomy, femoro-femoral arterial bypass was performed to prepare for the right common iliac artery resection. Thereafter, the patient underwent
laparotomy and
tumor resection combined with right
nephrectomy, resection of the right common iliac artery and vein, and resection of the right psoas muscle and femoral nerve. The postoperative course was uneventful, although the patient needed a walking
brace to support her gait. The pathological findings indicated a 99% disappearance of
tumor cells. The patient was healthy without any complaints after 1 year of surgery, and a follow-up CT scan revealed no
tumor recurrence.
CONCLUSIONS: To the best of our knowledge, this is the first report that showed a nearly complete pathological response to AI in dedifferentiated RPLS, which was subsequently completely resected.