Diagnostic work up
• Computed tomography (CT):
– Large lesions with fatty components causing mass effect
frequently represent liposarcomas.
– Teratomas often have fat, fluid, and calcified components.
– Paraspinal locations point to nerve sheath tumors or
neurogenic derivation .
• Magnetic resonance imaging (MRI) may demonstrate
additional imaging details to further classify the
lesion.
• CT-guided needle biopsy may be performed as the
initial means of obtaining tissue for histologic
diagnosis

RETROPERITONEAL SARCOMA
• Second most common malignant RPT.
• Arise from: nonepithelial, extraskeletal tissues:
(fat, muscle, nerve and nerve sheath, blood
vessels, other connective tissues).
• Incidence: 9,220 cases per year in the United
States.
• Common types:
– Leiomyosarcoma
– Liposarcoma
– Fibrosarcoma

• Primary treatment of retroperitoneal soft
tissue sarcoma (STS) is to attempt a gross total
resection.
• Criteria for unresectable tumors commonly
include major vessel invasion and spinal cord
or vertebral body involvement.
• Resectability has been reported in recent
series to range from 65% to 85%.

• Macroscopically positive margin is one the
most important prognostic features.
• Even after a complete excision of RPS, local
recurrence rates (33% to 77%) and overall
survival rates (35% to 63% 5-ys OS) are poor.
• retrospective data demonstrate a decrease in
local failure with adjuvant radiation therapy.

• Patients with unresectable disease:
– preoperative radiotherapy or chemotherapy in
attempt to shrink the tumor.
– Palliative debulking surgery may be offered.
• Patients with metastatic disease:
– Solitary or limited metastases:
• preoperative radiation therapy and/or chemotherapy,
metastasectomy, radiofrequency ablation. Chemotherapy
may be considered (most commonly, Doxorubicin-based
regimens).
– Disseminated metastatic disease:
• treated with palliative intent (chemotherapy, radiation
therapy, palliative surgery or best supportive care.)

Desmoid tumour
• Rare, benign neoplasms.
• Arise from muscle fascia, aponeuroses, tendons, and
scar tissue.
• More commonly in females .
• Associated with familial adenosis polyposis .
• locally aggressive and high chances to recur locally
after resection.
• Treatment is complete resection with a 2-3 cm margin.
• Postoperative radiation therapy is used in cases with an
unresectable primary, after multiple local recurrences.

Schwannomas
• Most common benign tumors in the retroperitoneum.
• Typically form large, well-circumscribed masses (may
display cystic degeneration, calcification, hemorrhage).
• MRI is the recommended imaging study.
• Not suggest CT-guided biopsy or fine-needle aspiration
for the diagnosis because of the risk of hemorrhage as
it is usually a highly vascular tumor.
• Complete surgical resection with negative margins is
the treatment of choice