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Developing a Treatment Plan for a Combined-type Retroperitoneal Liposarcoma
Bair, T., OMSIII; Munireddy, S., MD.
Roger Williams Medical Center, Division of Surgical Oncology, Providence, RI.
Introduction: Liposarcomas, although rare, are the most common type of soft tissue
sarcomas, affecting approximately 5,000 Americans per year. Patients typically present with a
palpable mass in the extremities or abdomen, with 10-15% occurring in the retroperitoneum.
Abdominal and retroperitoneal sarcomas commonly grow to great sizes before they are noticed
and diagnosed. This patient presented to her primary care physician with a six-month history
of progressive abdominal distension, and recent onset of urinary incontinence and right flank
discomfort. On CT scan she was found to have an extensive retroperitoneal mass that
completely surrounded her right kidney, and compressed her abdominal and pelvic contents
onto her left side. After a percutaneous biopsy, she was treated by surgical excision alone,
including a right nephrectomy. This case study explores the process of forming a cohesive
treatment plan for a rare disease using evidence-based diagnostic and treatment methods.
Case: A 69yo female presents on referral from her PCP for evaluation and treatment of a large
retroperitoneal mass. Her initial complaint was a 6-month history of increasing abdominal
distension, despite dieting and an intentional 6 lb weight loss. She also had a 2-3 week history
of urinary incontinence and right flank discomfort. She denied fever, chills, nausea, vomiting,
constipation, and changes in appetite. Her family history is significant for multiple cases of
breast and lung cancer. The patient has worked as a hairdresser for 47 years, quit smoking 36
yrs ago, and denies using alcohol or drugs. On physical exam her abdomen was soft, nontender,
and distended with dullness to percussion. She had a small umbilical hernia, and
enlarged veins over her anterior abdomen. A contrast enhanced CT scan of her abdomen and
pelvis showed an extensive retroperitoneal mass surrounding the right kidney, with areas of
variable enhancement with no liver lesions and CT scan of chest showed no lung lesions.
Radiation oncology was consulted regarding neoadjuvant radiotherapy, but due to the size and
extent of the tumor, and suspected minimal clinical benefit, it was not advised. The results of
an initial percutaneous biopsy showed a low-grade, well-differentiated liposarcoma, and the
TNM clinical staging at that time was T2bN0M0. A complete surgical resection was then
performed, including a right nephrectomy. Wide margins of 2cm were unachievable, due to the
tumor’s proximity to the IVC, aorta, and other vital structures. Because the current data does
not support any survival benefit for using adjuvant radiotherapy to prevent recurrence of
retroperitoneal liposarcomas, this treatment was not elected. Pathology classified the tumor
post-operatively as combined-type; primarily well-differentiated, with areas of dedifferentiated
liposarcoma. Her expected 5-year survival is between 60-100%. Metastasis is unlikely,
although recurrence is not uncommon. For this reason, the patient will be followed with
physical exams and CT scans of chest, abdomen and pelvis every 3-6 months for 2-3 years,
and then annually if there is no recurrence.
Discussion: Liposarcomas, like all sarcomas, are rare. However, because they can be locally
invasive and occasionally metastatic, proper diagnosis, treatment and follow-up procedures are
imperative. Depending on the location, grade and stage, treatment protocols for these tumors
may include neoadjuvant radiotherapy and/or chemotherapy, surgical excision, adjuvant
radiotherapy for preventing recurrence, and frequent follow-up exams. This case demonstrates
how to proceed through various evidence-based risk analyses in order to develop an
appropriate diagnostic and treatment plan for a patient with a rare, low-grade, combined-type
well-differentiated/dedifferentiated retroperitoneal liposarcoma.