The General Surgeon's quandary: atypical lipomatous tumor vs lipoma, who needs a surgical oncologist?
BACKGROUND
Differentiating large lipomas from atypical lipomatous tumors (ALT) is challenging, and preoperative management guidelines are not well defined. The diagnostic ambiguity leads many surgeons to refer all patients with large lipomatous masses to an oncologic specialist, perhaps unnecessarily.


METHODS
In this retrospective cohort study of patients with nonretroperitoneal lipomatous tumors, preoperative characteristics discernible without invasive diagnostic procedures were evaluated for diagnostic predictive value.


RESULTS
We identified 319 patients (256 with lipomas, 63 with ALTs) treated between 1994 and 2012. Patients with ALTs were older (60.5 vs 53.5 years, p < 0.0001), had larger tumors (16.0 vs 8.3 cm, p < 0.0001), had tumors more often located on an extremity (88.9% vs 60.5% torso, p < 0.0001), and more frequently had a history of previous operations at the same site, exclusive of excision leading to diagnosis and referral (20.6% vs 5.9%, p = 0.001). Local recurrence was observed in 2 patients with lipomas (0.8%) vs 14 with ALTs (22.6%, p < 0.0001). No patients with ALTs developed distant metastases or disease-specific mortality, with a median follow-up of 27.4 months (range 0 to 164.6 months). On multivariate analysis, age ≥ 55 years, tumor size ≥ 10 cm, extremity location, and history of previous resections were predictors for diagnosis of ALT (p < 0.05).


CONCLUSIONS
Characteristics of lipomatous masses associated with a diagnosis of ALT include patient age ≥ 55 years, tumor size ≥ 10 cm, previous resection, and extremity location (vs torso). These easily identifiable traits may guide surgical management or referral to a specialist.
Division of Surgical Oncology, Department of Surgery, Winship Cancer Institute, Emory University, Atlanta, GA.
Sarah B
SB
Fisher
Katherine J
KJ
Baxter
Charles A
CA
Staley
Kevin E
KE
Fisher
David K
DK
Monson
Douglas R
DR
Murray
Shervin V
SV
Oskouei
Sharon W
SW
Weiss
David A
DA
Kooby
Shishir K
SK
Maithel
Keith A
KA
Delman
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008067:Lipoma / Q000175:diagnosis* / Q000601:surgery*; D008297:Male; D008495:Medical Oncology; D008875:Middle Aged; D018205:Neoplasms, Adipose Tissue / Q000175:diagnosis / Q000601:surgery; D012017:Referral and Consultation; D012189:Retrospective Studies; D013043:Specialties, Surgical; D055815:Young Adult
ALT; DDLS; HR; ICD-9-CM; International Classification of Diseases, ninth revision, clinical modification; WDLS; atypical lipomatous tumor; dedifferentiated liposarcoma; hazard ratio; well-differentiated liposarcoma