Primary retroperitoneal neoplasms

Dr Owen Kang and Dr Jeremy Jones et al.

Primary retroperitoneal neoplasms are an extremely rare group of tumours (lymphoma is not included in this definition). The most common type is soft tissue sarcoma (90%).

The most common age for presentation is 40-50 years. 

Frequently tumours have relatively unimpeded growth where symptoms develop late and the tumour at presentation tending to be extremely large (average size 11-20 cm).

Primary retroperitoneal neoplasms arise from outside the major organs, and are divided according to histological types:

  • mesenchymal origin: skeletal muscle, fat, peripheral nerve, vessels, fibrous tissue
  • extra-gonadal germ cell tumours
  • primary retroperitoneal adenocarcinoma

The order of frequency of primary retroperitoneal malignancy is as follows:

Causes include radiotherapy, e.g. neuroblastoma treatment as a child. 

Imaging is used to confirm diagnosis, assess for any metastatic disease and determine the potential for resection. CT is the most commonly used tool. MRI can be used for further differentiation, but histology is always required.

Percutaneous biopsy may be undertaken (after consultation with surgeons and oncologists) and for assessment of tumour grade PET may be used 2

Prognosis depends on the histological type of tumour and the potential for resection.

Recurrence rates are high (90% in some series), so imaging surveillance is an important part of continued follow up.

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Article information

rID: 6336
Synonyms or Alternate Spellings:
  • Primary retroperitoneal malignancy
  • Primary retroperitoneal neoplasm
  • Primary retroperitoneal tumours

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Cases and figures

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    Case 1: retroperitoneal liposarcoma
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    Case 2: retroperitoenal rhabdomyosarcoma
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     Case 3
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    Case 4: massive liposarcoma
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    Case 5: malignant peripheral nerve sheath tumor
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