AUTHOR=Bird Justin E. , Morse Lee Jae , Feng Lei , Wang Wei-Lien , Lin Patrick P. , Moon Bryan S. , Lazar Alexander J. , Satcher Robert L. , Madewell John E. , Lewis Valerae O. TITLE=Non-Radiographic Risk Factors Differentiating Atypical Lipomatous Tumors from Lipomas JOURNAL=Frontiers in Oncology VOLUME=6 YEAR=2016 URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2016.00197 DOI=10.3389/fonc.2016.00197 ISSN=2234-943X ABSTRACT=Purpose

To determine non-radiographic risk factors differentiating atypical lipomatous tumors (ALTs) from lipomas.

Methods

All patients with deep-seated lipomatous tumors of the extremities treated from January 2000 to October 2010 were retrospectively reviewed. Factors reviewed included age, gender, tumor location, size, histology, local recurrence, dedifferentiation, and metastasis. Multivariate logistic regression models were used to evaluate the effects of patient characteristics on ALT status.

Results

Ninety-four lipomas and 46 ALTs were included. Patients with an ALT were older (median: 60.5 vs. 55 years). Lipomas were evenly distributed between upper (48.9%) and lower extremities (51.1%), whereas ALTs predominately involved the lower extremities (91.3%). Median ALT size (22 cm) was greater than lipomas (10 cm), p < 0.0001. One lipoma (1.04%) recurred at 77 months and five ALTs (10.9%) recurred at an average of 39 months (19–64 months). Two ALTs originally treated with wide resection recurred with a dedifferentiated component and were treated with wide re-excision and chemotherapy. No metastases or tumor-related deaths occurred in either group at the time of last follow-up. Patients older than 60 years, tumors greater than 10 cm, or thigh location, were more likely to be diagnosed with an ALT (p < 0.05).

Conclusion

Lipomatous tumors were more likely to be ALTs when the tumor was at least 10 cm in size, located in the thigh, or found in patients that were 60 years of age or older. These risk factors may be used to guide management and surveillance strategies, when lipomatous tumors do not display characteristic radiographic features.