Staging and Surveillance of Myxoid Liposarcoma: Follow-up Assessment and the Metastatic Pattern of 169 Patients Suggests Inadequacy of Current Practice Standards.

Background: Unlike other sarcoma subtypes, myxoid liposarcoma (MLS) has a propensity for extra-pulmonary metastases. Computed tomography (CT) scan of the chest, abdomen, and pelvis has become an accepted practice for surveillance. However, recent literature suggests that this may be inadequate. This study aimed to assess the ability of current imaging methods to detect metastases adequately in this population.

Methods: The study identified 169 patients with MLS diagnosed between 2000 and 2016. The timing and location of metastases, the reasons leading to the MLS diagnosis, and the imaging methods were recorded. The locations of metastases were classified into the following categories: pulmonary, soft tissue, bone, retroperitoneal, intraperitoneal, solid organ, and lymph node.

Results: An initial diagnosis of metastasis was made at presentation with staging CT scan for 3 (10 %) of 31 patients, with a follow-up surveillance CT scan for 15 (48 %) of the patients or with subsequent imaging obtained in response to patient-reported symptoms for 13 (42 %) of the patients. The proportions of patients who had metastases in each location were as follows: soft tissue (84 %), pulmonary (68 %), intraabdominal (48 %), solid organ (48 %), bone (45 %), lymph node (32 %), and retroperitoneal (29 %). Although 14 patients had bone metastases, only 1 patient had a sclerotic/blastic presentation visualized on CT scan, and the diagnosis for the remaining 13 patients was determined by magnetic resonance imaging (MRI).

Conclusion: Due to metastatic disease identified outside surveillance imaging for 58 % of the patients, the diversity of locations, and the significant failure of CT and bone scan to identify bone metastases, this study questioned the adequacy of CT scan for surveillance of MLS. Consideration should be given to the use of whole-body MRI for detection of metastasis in MLS.