Retroperitoneal tumors

tumors are malignant and arise from a mesenquimatous origin. Usually involving important anatomical structures such as main abdominal vessels and organs, their radical approach often necessitates major resections of these viscera.
Surgery of the inferior vena cava
Inferior vena cava involvement by primary and secondary tumors has been traditionally considered an unresectability criterion. Currently, thanks to the technical development of surgery (mainly after liver transplantation development) and the creation of new prosthetic materials for vascular repair, inferior vena cava resections are feasible and safe in a selected group of patients.
 
The retroperitoneum is the anatomical space limited by the peritoneum at the front, the abdominal wall at the back, the twelfth rib at the top, and the sacrum and crest of the ileum at the lower side. Some organs, such as the kidneys, ureters, and adrenal glands are located in this space.
 
The primary retroperitoneal tumors develop a great variety of neoplasia due to their histogeny. Most primary retroperitoneal tumors are malignant and have a mesenchymal origin. They represent the 0.3% to 0.8% of all types of neoplasia.
 
Their clinic occurrences are seldom and not precise, but when present, the retroperitoneal tumors normally appear in later stages and are caused by compression or movement of organs or near-by structures.
 
The liposarcoma is the most frequent malignant retroperitoneal tumor and is one of the most common sarcomas among all possible locations (25-35%).
 
The pleomorphic and lipomatous are the most usual types. The malignant fibrous histiocytoma is a common neoplasy in the elderly and in extremities of soft tissue. In the retroperitoneum, the most frequent histological variety is the pleomorphic one. The leiomyosarcoma can be present at different locations and the evaluation of the number of atypical mitosis prior to evaluating the retroperitoneal tumors malignancy is necessary.
 
Those retroperitoneal tumors located in the retroperitoneum have a bigger size, indicating malignancy itself. They frequently present Schimmelbusch's disease and necrosis.
 
The schwannomas or nerve sheath tumors can appear at any age, and those located in the retroperitoneal area usually present a big size. Morphologically speaking, they can be identified by the presence of fusiform, wavy cells that tend to form palisades. Chromaffinomas are tumors formed in chromaffin-cell groups and they synthesize catecholamines and other amines. They are connected to the sympathetic and parasympathetic nervous systems. The tumors originated in these structures are called chromaffinomas. Extra-adrenal chromaffinomas are present in the midline, especially in the upper or lower para-aortic region. One of the most frequent origins is the Zuckerkandl organ. Extraadrenal chromaffinomas are usually functional: they produce high levels of catecholamine and are responsible for clinic manifestations such as arterial hypertension.
 
In most cases, the presence of germinal retroperitoneal tumors represents metastasis of primary gonad tumors. In adults, the most frequent types are the seminoma, followed by the embryonic carcinoma and teratoma. In children, mature and immature, teratomata are more frequent, whereas the embryonic carcinoma and the endodermic sinus tumor are less common. Signs and symptoms are generally quite unspecific and they appear due to the compression of the structure of nearby organs.
 
Radiologic explorations, helical computed tomographies and resonance angiographies facilitate the diagnosis of the injury as well as its vascular connections.
 
The involvement of the inferior vena cava in tumoral processes has been considered for a very long time an unquestionable reason for surgical inoperability or unresectability.
 
The great difficulty of this technique and the unclear risk/benefit relation are important reasons which determine this attitude.
 
The important progress made in the last two decades for the inferior vena cava surgery (most of them thanks to liver transplant) and the use of new prosthetic materials have permitted vena cava resections, with or without substitute prosthesis, as a therapeutic alternative for patients with locally-advanced tumoral diseases. Thus, a therapeutic approach may be offered to a particular number of patients with a curative intention.
 
Our experience in resection of the inferior vena cava following different process goes up to 20 different cases. The indications for their performance were:
 
- Liver metastasis from colorectal carcinoma
- Intrahepatic cholangiocarcinoma
- Renal carcinoma
- Inferior vena cava tumoral thrombosis from renal carcinoma
- Inferior vena cava primary tumors
- Retroperitoneal tumors with involvement of the inferior vena cava
- Liver hydatid disease with involvement of the inferior vena cava and consequent thrombosis
In 40% of the cases described, a resection of the inferior vena cava and a restitution of the systemic vascular flow were performed thanks to a ring prosthesis 20 mm diameter. In most cases, a saphenous-femoral arterio-venous fistula was added in order to increase venous flow in the prosthesis.
 
The results obtained, in terms of surgical morbimortality, permeability of the substitute prosthesis, and long, medium and short term survival rates justify this kind of surgical procedures in a particular number of patients in which a venous excision might be required for the complete resection of the tumor. As long as the characteristics of the tumor require it, following chemoradiotherapy completes the therapeutic treatment.