The Utility of Chest Imaging for Surveillance of Atypical Lipomatous Tumors

Abstract

Synopsis. For ALTs, the utility of chest surveillance has not been well defined. This study suggests that chest imaging does not have a significant role in the surveillance of ALTs. Advanced local imaging and more intensive chest surveillance may be considered in cases of local recurrence. Background. Unlike other soft tissue sarcomas, atypical lipomatous tumors (ALTs) are thought to have a low propensity for metastasis. Despite this, a standard of care for pulmonary metastasis (PM) surveillance has not been established. This study aimed to evaluate the utility of chest imaging for PM surveillance following ALT excision. Methods. This was a multi-institution, retrospective review of all patients with primary ALTs of the extremities or superficial torso who underwent excision between 2006 and 2018. Minimum follow-up was two years. Long-term survival was evaluated using the Kaplan–Meier method. Results. 190 patients with ALT were included. Average age was 61.7 years and average follow-up was 58.6 months (24 to 180 months). MDM2 testing was positive in 88 patients (46.3%), and 102 (53.7%) did not receive MDM2 testing. 188 patients (98.9%) had marginal excision, and 127 (66.8%) had marginal or positive margins. Patients received an average of 0.9 CT scans and 1.3 chest radiographs over the surveillance period. 10-year metastasis-free survival was 100%, with no documented deaths from disease. Conclusions. This study suggests that chest imaging does not have a significant role in PM surveillance following ALT excision, but advanced local imaging and chest surveillance may be considered in cases of local recurrence or concern for dedifferentiation.

Adjuvant Radiation after Primary Resection of Atypical Lipomatous Tumors of the Extremity Reduces Local Recurrence but Increases Complications: A Multicenter Evaluation

“…Lastly, though not specifically surveyed with routine chest imaging in this study, there were no documented lung metastases at final follow-up based on a review of medical records. This finding supports the recent findings of a study by Lazarides et al recommending against routine chest imaging in patients with an ALT [ 3 ].…”

“…In this study, the proportion of patients without MDM2 results was not significantly different in the XRT and no-XRT groups, thereby theoretically lessening the impact of potential selection bias, and MDM2 status was not found to be an independent predictor of recurrence in our multivariable analysis. Other recent studies of ALT have shown histologic criteria without MDM2 testing to be an acceptable definition for patient inclusion, as Lazarides et al also demonstrated no difference in recurrence rate between MDM2 -positive tumors and those in which MDM2 FISH was not performed [ 3 ]. A final limitation of this study is the inability to account for the variability of radiation delivery.…”

“…In the retroperitoneum or other deep anatomic locations, they are still considered welldifferentiated liposarcomas (WDL). is distinction is important, since in contrast to WDL, ALTs are indolent, locally aggressive neoplasms that infrequently dedifferentiate and develop metastatic potential (1.5-6.5%) [1][2][3][4][5]. A definitive diagnosis is based on either characteristic histologic findings or confirmation of MDM2 gene amplification [6,7].…”

“…A definitive diagnosis is based on either characteristic histologic findings or confirmation of MDM2 gene amplification [6,7]. ALTs carry a noteworthy risk of local recurrence, ranging between 9 and 43% in the extremities and trunk [1][2][3][8][9][10][11]. Due to the indolent nature of these lesions, widely accepted treatment is marginal (R1) resection similar to a lipoma [12,13], although some centers have reported decreased rates of local recurrence with wide (R0) resection [1].…”

Tumor-to-bone distance and radiomic features on MRI distinguish intramuscular lipomas from well-differentiated liposarcomas

“…ALTs characterize extremity or upper trunk lesions, and WDLSs represent retroperitoneal or mediastinal lesions. ALTs/WDLSs are low-grade, malignant, adipocytic tumors that recur locally or dedifferentiate to high-grade sarcomas, but they rarely metastasize [ 6 , 7 ]. The gold standard for the diagnosis of ALTs/WDLSs is histopathological evidence of lipoblasts and lipocytes, with immunohistopathological staining positive for murine double minute 2 (MDM2) or cyclin-dependent kinase 4 (CDK4) [ 8 , 9 ].…”