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Retroperitoneal Neoplasm

Retroperitoneal neoplasms include benign and malignant tumors that emerge within the retroperitoneum. These are rarely encountered in the clinical practice. Lymphoma is by far the most important malignant retroperitoneal neoplasm, followed by liposarcoma, leiomyosarcoma and malignant fibrous histiocytoma, whereas a number of benign lesions are described in the literature. Symptoms in the form of abdominal pain, a palpable abdominal mass and distension, usually appear when the tumor is very large. Computed tomography (CT) and magnetic resonance imaging (MRI) are used to make the diagnosis.


Retroperitoneal neoplasms encompass tumors of different origins and nature (benign or malignant) that arise within this anatomical structure, but outside of the organs situated in the retroperitoneum [1] [2] [3] [4]. Some of the most important retroperitoneal neoplasms are [5] [6]:

  • Lymphomas - Representing about 33% of all retroperitoneal malignant tumors, both non-Hodgkin and Hodgkin lymphomas may become apparent [3].
  • Mesodermal tumors - Leiomyosarcoma, liposarcoma, and malignant fibrous histiocytoma comprise more than 80% of all sarcomatous tumors of the retroperitoneum [2] [5] [6]. Rhabdomyosarcomas, angiosarcomas, and chondrosarcomas are less common malignancies encountered in the retroperitoneum, together with fibromas, lipomas, and leiomyomas as their benign variants [2] [5].
  • Neurogenic tumors - Schwannomas, ganglioneuromas, and neurofibromas are main benign lesions of the nervous tissue, whereas neurogenic sarcomas, neurofibrosarcomas, neuroblastoma and malignant schwannomas are notable malignant counterparts [3] [5].
  • Sex cord tumors - About 1%-2.5% of gonadal tumors originate in extragonadal sites, and the peritoneum is one of them [3].

The clinical course of a retroperitoneal neoplasm is predominantly described as insidious, mainly because the tumor needs to grow considerably in size before producing symptoms [2] [4] [5]. Main complaints, when present, are abdominal pain, distension, and a palpable abdominal mass, while early satiety, abdominal swelling, and gastrointestinal/urinary symptoms, which were thought to be rare, are seen in up to 40-50% of cases [2] [3] [4] [5].

Soft Tissue Mass
  • Rarely, thrombosis of an anomalous retroperitoneal vein may resemble a soft tissue mass. Awareness of this fact helps preventing unnecessary interventions.[ncbi.nlm.nih.gov]
  • -29: 0.0 % 30-39: 0.0 % 40-49: 0.0 % 50-59: 0.0 % 60 : 100 % Top other side effects for these people *: Prostatitis (inflammation of the prostate gland): 2 people, 100.00% Pancreatitis Acute (sudden inflammation of pancreas): 2 people, 100.00% Gouty Arthritis[ehealthme.com]


Because of a rather nonspecific (or even absent) clinical presentation, the diagnosis of a retroperitoneal neoplasm may be difficult to make. For this reason, the physician plays a crucial role when obtaining a detailed patient history and performing a thorough clinical examination. To identify the exact location of the tumor and determine its subtype, however, imaging studies need to be carried out. CT and MRI are the two main exams used in the assessment of the retroperitoneum [1] [3] [4] [5] [6]. Several findings that point to a retroperitoneal neoplasm are embedded organ sign (compression of the adjacent organ into a crescent shape), prominent feeding artery sign (hypervascularization of the presenting mass), and the presence of dull edges of the organ adjacent to the tumor [1]. Tumor types may be further discriminated by their distinguishing features:

  • Liposarcoma - High signal intensity on T1-weighted studies, intermediate T2-weighted signal, and complete loss of fat signal intensity on MR images that suppress the fatty tissue [3].
  • Leiomyosarcoma - Intermediate-to-low signal intensity on T1 and intermediate-to-high on T2 is typical, depending on the extent of necrosis [3].
  • Malignant fibrous histiocytoma - A large-infiltrating and heterogeneous necrotic and hemorrhagic mass [3].
  • Lymphoma - A well-defined homogeneous lump that mechanically compresses the major blood vessels [3].
  • Schwannomas - Well-defined cystic masses with smooth margins [5].
  • Tumor types may be further discriminated by their distinguishing features: Liposarcoma - High signal intensity on T1-weighted studies, intermediate T2-weighted signal, and complete loss of fat signal intensity on MR images that suppress the fatty tissue[symptoma.com]


  • Treatment and prognosis Prognosis depends on the histological type of a tumor and the potential for resection.[radiopaedia.org]
  • A literature review using PubMed is also presented, discussing several issues concerning clinicopathologic features, treatment options, and long-term outcome of PRMCN.[ingentaconnect.com]
  • Symptoms and treatment depend on the cancer type and how advanced it is. Most treatment plans may include surgery, radiation and/or chemotherapy.[icdlist.com]
  • Peritoneal Cancer Treatments You may have more than one type of treatment for peritoneal cancer.[webmd.com]
  • The current volume of with musculoskeletal cancers has been the aggressive Musculoskeletal Cancer Surgery: Treatment of Sarcomas and resection of metastatic deposits.[books.google.ro]


  • Treatment and prognosis Prognosis depends on the histological type of a tumor and the potential for resection.[radiopaedia.org]
  • Long-term follow-up is lacking, although it is important to better define the prognosis of PRMCN. No Reference information available - sign in for access. No Citation information available - sign in for access. No Supplementary Data.[ingentaconnect.com]
  • Prognosis is affected by age and site. Those under two years and those with pelvic tumors have a better prognosis. Overall prognosis is poor. 2.[urologyweb.com]
  • Encyclopedia) Hyperthermia for treating cancer (Medical Encyclopedia) Laser therapy for cancer (Medical Encyclopedia) Photodynamic therapy for cancer (Medical Encyclopedia) Targeted therapies for cancer (Medical Encyclopedia) Understanding your cancer prognosis[icdlist.com]
  • Peritoneal Cancer Prognosis: What to Expect Primary peritoneal cancer prognosis is best if all cancer is removed and a gynecologic surgeon and oncologist treat you. These doctors have special knowledge of gynecologic cancers.[webmd.com]


  • […] neoplasms arise from outside the major organs, and are divided according to histological types: mesenchymal origin : skeletal muscle, fat, peripheral nerve, vessels, fibrous tissue extragonadal germ cell tumors primary retroperitoneal adenocarcinoma Etiology[radiopaedia.org]
  • In most patients (approximately 68%), no etiologic factor is found. Therefore, the term idiopathic RFP is used.[emedicine.medscape.com]


  • […] of Surgical Oncology, Mount Sinai Hospital and Princess Margaret Cancer Center, Department of Surgery, University of Toronto, Toronto, Canada. 2 Department of Surgery, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. 3 Unit of Clinical Epidemiology[ncbi.nlm.nih.gov]
  • Definition / general Smooth muscle tumor with atypia plus either mitotic activity, tumor cell necrosis or size 10 cm 10% of adult soft tissue sarcomas Variants are described separately above Epidemiology Skin / subcutis: see cutaneous variants above;[pathologyoutlines.com]
  • Soft tissue sarcoma across the age spectrum: a population-based study from the Surveillance Epidemiology and End Results database. Pediatr Blood Cancer. 2011 Dec;57(6):943–9. Karadayi K, Yildiz C, Karakus S, Kurt A, Bozkurt B, Soylu S et al.[karger.com]
Sex distribution
Age distribution


  • Awareness of this fact helps preventing unnecessary interventions. We report a case of thrombosis of retroaortic left renal vein and interrupted IVC that mimicked a retroperitoneal neoplasm.[ncbi.nlm.nih.gov]
  • Click here to view the NCCN Guidelines Panel Members individual disclosures NCCN Guidelines for Treatment of Cancer by Site NCCN Guidelines for Detection, Prevention, & Risk Reduction NCCN Guidelines for Supportive Care NCCN Guidelines for Age Related[nccn.org]
  • […] and early detection of cervical cancer: American Cancer Society, American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology screening guidelines for the prevention and early detection of cervical cancer.[nccn.org]
  • NIH: National Cancer Institute Cancer (Medical Encyclopedia) Cancer and lymph nodes (Medical Encyclopedia) Cancer treatment -- early menopause (Medical Encyclopedia) Cancer treatment: preventing infection (Medical Encyclopedia) Cancer treatments (Medical[icdlist.com]



  1. Nishino M, Hayakawa K, Minami M, Yamamoto A, Ueda H, Takasu K. Primary retroperitoneal neoplasms: CT and MR imaging findings with anatomic and pathologic diagnostic clues. Radiographics. 2003;23(1):45-57.
  2. Brennan C, Kajal D, Khalili K, Ghai S. Solid malignant retroperitoneal masses—a pictorial review. Insights into Imaging. 2014;5(1):53-65.
  3. Rajiah P, Sinha R, Cuevas C, Dubinsky TJ, Bush WH Jr, Kolokythas O. Imaging of uncommon retroperitoneal masses. Radiographics. 2011;31:949–976.
  4. Strauss DC, Hayes AJ, Thomas JM. Retroperitoneal tumours: review of management. Ann R Coll Surg Engl. 2011;93(4):275-280.
  5. Wee-Stekly W-W, Mueller MD. Retroperitoneal Tumors in the Pelvis: A Diagnostic Challenge in Gynecology. Front Surg. 2014;1:49.
  6. Gemici K, Buldu İ, Acar T, et al. Management of patients with retroperitoneal tumors and a review of the literature. World J Surg Oncol. 2015;13:143.

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Last updated: 2018-06-21 22:24