Retroperitoneal Sarcoma

• • Mesenchymal-derived soft-tissue neoplasms

  • Metastasize via the hematogenous route with the majority of metastases to the liver or lung

  • Behavior tends to be dictated by tumor grade rather than cell type of origin

  • Rarely cause symptoms until they grow to a large size

  • Vague abdominal symptoms are the most common presenting complaint

Epidemiology

• • Account for 15% of all sarcomas and 55% of all retroperitoneal tumors

  • Most common variant is a liposarcoma

Symptoms and Signs

• • Nonspecific vague abdominal symptoms most common complaint

  • Abdominal discomfort

  • Early satiety

  • Nausea and vomiting

  • Weight loss

  • Palpable abdominal mass

Laboratory Findings

• • A small percentage of patients present with hypoglycemia simulating an insulinoma

Imaging Findings

• • Chest film or thoracic CT scan: May demonstrate pulmonary metastases

  • Abdominal CT scan or MRI

  • -Demonstrates the soft-tissue neoplasm and its relationship to adjacent retroperitoneal structures

    -MRI is typically more accurate than CT scan in defining the extent of tumor and invasion of surrounding structures

• • Retroperitoneal sarcoma

  • Retroperitoneal teratoma

  • Retroperitoneal cyst

  • Retroperitoneal abscess

  • Retroperitoneal hematoma

  • Mesenteric cyst

  • Mesenteric lipodystrophy

  • Pseudomyxoma peritonei

  • Malignant peritoneal mesothelioma

  • Adrenal mass

  • Renal cell carcinoma

  • Intra-abdominal process with retroperitoneal extension

Rule Out

• • Retroperitoneal abscess

  • Retroperitoneal hematoma

  • Adrenal mass

  • Renal cell carcinoma

  • Intra-abdominal process with retroperitoneal extension

• • Thorough history and physical exam

  • Abdominal pelvic CT scan or MRI (preferred) to evaluate extent of lesion

  • Chest film or thoracic CT scan to evaluate for metastatic disease

  • Image-guided core needle biopsy vs open/laparoscopic incisional biopsy to establish diagnosis

When to Admit

• • Work-up of these lesions can usually be performed as an outpatient

  • Admission for bowel obstruction or other tumor-related complications

When to Refer

• • Multidisciplinary management of retroperitoneal tumors essential to ensure accurate diagnosis and appropriate treatment:

  • -Surgeon

    -Medical oncologist

    -Radiation oncologist

    -Pathologist

    -Radiologist

• • Neoadjuvant chemoradiation

Surgery

• • Complete surgical extirpation with in-bloc resection of involved structures

Indications

• • Operative excision in all patients without evidence of metastases and where all gross tumor can be removed (approximately 50% of cases)

  • Resection of pulmonary metastases should be considered in patients who have achieved local control and who have less than 4 pulmonary lesions

Contraindications

• • Widespread metastatic disease

  • Inability to resect all grossly evident tumor

  • Tumor involvement of adjacent retroperitoneal structures is not a contraindication as long as they can be resected in continuity with the primary lesion