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Irregular Lipomatous Extremity Tumor

Educational Objective
Based on this clinical scenario and the accompanying image, understand how to arrive at a correct diagnosis.
1 Credit CME

A 71-year-old otherwise healthy woman presented with an enlarging, immobile, painless mass in her right gluteal area. She had no other associated symptoms. On examination, she had a large, palpable, nontender right gluteal mass. She had no neurovascular deficits. Results of laboratory studies were within normal limits. Computed tomography (CT) revealed an 11-cm heterogeneous lipomatous tumor involving the right gluteal musculature (Figure).

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Well-differentiated/dedifferentiated liposarcoma

B. Core needle biopsy of the lesion

Core needle biopsy should be performed to obtain tissue diagnosis. Incisional biopsy should be avoided and can complicate surgical and oncologic management.1 Surgical management should be deferred until a tissue diagnosis is made and preoperative workup is complete. Because this tumor is enlarging, larger than 5 cm, deep (subfascial), and heterogeneous, it should be considered malignant until proven otherwise. Repeat imaging is unnecessary and likely would be inadequate.

Liposarcomas are rare, often aggressive, malignancies that require surgical resection and multidisciplinary management. There are approximately 2400 new cases of liposarcoma diagnosed in the United States per year.2,3 Subtypes of liposarcoma include well-differentiated, dedifferentiated, myxoid, and pleomorphic. A well-differentiated liposarcoma of the extremity may also be referred to as an atypical lipomatous tumor.

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Article Information

Corresponding Author: Fritz C. Eilber, MD, Division of Surgical Oncology, University of California, Los Angeles, 10833 Le Conte Ave, 54-140 CHS, Los Angeles, CA 90095 (fceilber@mednet.ucla.edu).

Published Online: April 5, 2019. doi:10.1001/jama.2019.3719

Conflict of Interest Disclosures: Dr Eilber reported serving as a member of the scientific advisory board of Certis Oncology. No other disclosures were reported.

Additional Contributions: We thank the patient for providing permission to share her information.

References
1.
Wilkinson  MJ, Martin  JL, Khan  AA, Hayes  AJ, Thomas  JM, Strauss  DC.  Percutaneous core needle biopsy in retroperitoneal sarcomas does not influence local recurrence or overall survival.  Ann Surg Oncol. 2015;22(3):853-858. doi:10.1245/s10434-014-4059-xPubMedGoogle ScholarCrossref
2.
Adult Soft Tissue Sarcoma Treatment (PDQ®)–Health Professional Version. National Cancer Institute website. https://www.cancer.gov/types/soft-tissue-sarcoma/hp/adult-soft-tissue-treatment-pdq. Updated January 29, 2019. Accessed March 11, 2019.
3.
Brennan  MF, Antonescu  CR, Moraco  N, Singer  S.  Lessons learned from the study of 10,000 patients with soft tissue sarcoma.  Ann Surg. 2014;260(3):416-421. doi:10.1097/SLA.0000000000000869PubMedGoogle ScholarCrossref
4.
Clay  MR, Martinez  AP, Weiss  SW, Edgar  MA.  MDM2 amplification in problematic lipomatous tumors: analysis of FISH testing criteria.  Am J Surg Pathol. 2015;39(10):1433-1439. doi:10.1097/PAS.0000000000000468PubMedGoogle ScholarCrossref
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Traub  F, Griffin  AM, Wunder  JS, Ferguson  PC.  Influence of unplanned excisions on the outcomes of patients with stage III extremity soft-tissue sarcoma.  Cancer. 2018;124(19):3868-3875. doi:10.1002/cncr.31648PubMedGoogle ScholarCrossref
6.
Sommerville  SM, Patton  JT, Luscombe  JC, Mangham  DC, Grimer  RJ.  Clinical outcomes of deep atypical lipomas (well-differentiated lipoma-like liposarcomas) of the extremities.  ANZ J Surg. 2005;75(9):803-806. doi:10.1111/j.1445-2197.2005.03519.xPubMedGoogle ScholarCrossref
7.
O’Sullivan  B, Davis  AM, Turcotte  R,  et al.  Preoperative versus postoperative radiotherapy in soft-tissue sarcoma of the limbs: a randomised trial.  Lancet. 2002;359(9325):2235-2241. doi:10.1016/S0140-6736(02)09292-9PubMedGoogle ScholarCrossref
8.
Woll  PJ, Reichardt  P, Le Cesne  A,  et al; EORTC Soft Tissue and Bone Sarcoma Group and the NCIC Clinical Trials Group Sarcoma Disease Site Committee.  Adjuvant chemotherapy with doxorubicin, ifosfamide, and lenograstim for resected soft-tissue sarcoma (EORTC 62931): a multicentre randomised controlled trial.  Lancet Oncol. 2012;13(10):1045-1054. doi:10.1016/S1470-2045(12)70346-7PubMedGoogle ScholarCrossref
9.
Eilber  FC, Brennan  MF, Eilber  FR, Dry  SM, Singer  S, Kattan  MW.  Validation of the postoperative nomogram for 12-year sarcoma-specific mortality.  Cancer. 2004;101(10):2270-2275. doi:10.1002/cncr.20570PubMedGoogle ScholarCrossref
10.
Gutierrez  JC, Perez  EA, Moffat  FL, Livingstone  AS, Franceschi  D, Koniaris  LG.  Should soft tissue sarcomas be treated at high-volume centers? an analysis of 4205 patients.  Ann Surg. 2007;245(6):952-958. doi:10.1097/01.sla.0000250438.04393.a8PubMedGoogle ScholarCrossref
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