Sreeharsha Tirumani MBBS, MD, Presenter: Nothing to Disclose

Harika Tirumani MBBS, Abstract Co-Author: Nothing to Disclose

Jyothi Priya Jagannathan MD, Abstract Co-Author: Nothing to Disclose

Atul Bhanudas Shinagare MD, Abstract Co-Author: Nothing to Disclose

Nikhil H. Ramaiya MD, Abstract Co-Author: Nothing to Disclose

Retroperitoneal Dedifferentiated liposarcoma (DDLPS) is a heterogeneous tumor on imaging with different densities on CT, and biologically varied with different growth rates. In this study, we retrospectively correlated effect of treatment on different densities in DDLPS.

In this institutional review board-approved, retrospective study, out of 111 patients with primary or recurrent retroperitoneal/intra-abdominal DDLPS seen between January 1999 and December 2013, 25 patients (18 men, 7 women; mean age at diagnosis= 58 years, range, 35-72years) who received chemotherapy, radiotherapy or both before surgical resection were included. Imaging immediately prior to surgical resection (pre-surgery) and at baseline was reviewed by two radiologists to note the density of the nonlipomatous elements and the rate of growth during that period. Clinical and histopathological data was extracted from the electronic medical records.

There were 37 nonlipomatous lesions with three distinct densities: soft tissue density (SD) (>20HU), fluid density (FD) (0-20HU), and mixed density (MD) (combination of fluid and soft tissue). The distribution of the densities on the baseline scan and pre-surgery scans were SD=23; MD=9; FD=5 and SD=23; MD=11; FD=3 respectively. There was decrease in size of three lesions (>30%) while the rest 34 lesions were either unchanged in size or increased in size (26/34 lesions showed an increase in size by >20%). The respective median growth rate per month was 39% (SD), 63% (MD), and 35% (FD). There was a change in density in 2/23 SD lesions (to MD) and 2/5 FD lesions (to SD). Tumors were intermediate (10SD, 6MD, 4FD) or high (13SD, 3MD, 1FD) grade.

The nonlipomatous component of retroperitoneal DDLPS has three distinct densities on imaging which tend to grow at different rates despite treatment and can change their density in response to treatment. The densities do not correlate with the histological grade.

Knowledge of the occurrence of different densities in the nonlipomatous component of retroperitoneal DDLPS can help radiologists to exert caution while interpreting images. Targeted biopsies in the future can help in understanding the histopathologic relevance of the different densities.

Tirumani, S, Tirumani, H, Jagannathan, J, Shinagare, A, Ramaiya, N, Effect of Treatment on Different CT Densities in Retroperitoneal Dedifferentiated Liposarcoma Treated with Chemotherapy or Radiotherapy prior to Surgical Resection.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14009641.html