Retroperitoneal Liposarcoma
A 60-year-old woman reports six months of dull abdominal aching with 8 kg weight loss. Examination reveals a firm, non-tender 20 cm by 20 cm intra-abdominal mass. CT shows a lobulated fat containing soft tissue mass arising from the retroperitoneum with multiple hypodense liver lesions and no lymphadenopathy. Which of the following is the most likely diagnosis?
- A.LiposarcomaCorrect
- B.Germ cell tumor
- C.Peripheral nerve sheath tumor
- D.Lymphoma
Explanation
Liposarcoma is the commonest primary soft tissue sarcoma of the retroperitoneum in adults and fits every element of this presentation. It arises from adipocyte precursors, which is why CT typically shows a large lobulated mass containing macroscopic fat with soft tissue nodularity. Peak incidence is between the fifth and seventh decades, matching this 60-year-old patient. These tumors grow slowly to enormous size and produce only vague symptoms such as dull ache, abdominal swelling, early satiety and weight loss, exactly as described. The absence of enlarged lymph nodes further supports a primary sarcoma, because sarcomas disseminate haematogenously and the hypodense liver lesions here represent metastases rather than nodal disease. Lymphoma characteristically produces bulky mesenteric and para-aortic lymphadenopathy encasing vessels, which is absent. Germ cell tumors of the retroperitoneum occur in men in their twenties and thirties and are associated with raised alpha-fetoprotein or beta human chorionic gonadotropin. Peripheral nerve sheath tumors are much rarer, usually paraspinal, and often occur in neurofibromatosis type 1. Diagnosis is confirmed by image guided core biopsy and treatment is en bloc resection at a sarcoma centre, with grade and completeness of resection determining prognosis.
Why each option
- A.
- Correct. A large lobulated fat containing retroperitoneal mass in a patient in their sixties with vague ache and weight loss is characteristic of liposarcoma.
- B.
- Primary retroperitoneal germ cell tumors occur in young men, usually with elevated alpha-fetoprotein or beta human chorionic gonadotropin, and are far less common in this setting.
- C.
- Peripheral nerve sheath tumors are uncommon retroperitoneal masses, tend to be paraspinal, and are typically associated with neurofibromatosis type 1.
- D.
- Retroperitoneal lymphoma typically presents with bulky para-aortic and mesenteric lymphadenopathy that encases vessels, and no lymphadenopathy is present here.
Reference: Sabiston Textbook of Surgery, 21st ed., 2022, Soft Tissue Sarcoma
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