Retroperitoneal tumor

The commonest malignant cause of mid-ureteric obstruction is extrinsic compression by metastatic lymphadenopathy retroperitoneal tumors are less common and are listed in Table 7.1. 

Pre- and post-contrast series are combined. Time delay should be adapted to pathology arterial time should be acquired in the context of trauma or tumor. Very delayed acquisition can sometimes be necessary to look for stagnant iodine within the parenchyma in acute pyelonephritis (Ishikawa et al. 1985 Dalla Palma et al. 1995) or a peri-renal leak in cases of renal fracture. Two-dimensional reformatting is especially useful in evaluating renal fractures or retroperitoneal tumors (Fig. 1.1.9). Maximal intensity projection images in the coronal and sagittal planes advantageously replace IVU at any time of the examination. 

Retrocaval ureter causes a typical medial displacement of the right lumbar ureter that is appreciated on IVU (Fig. 5.27), but best demonstrated on CT. Ischiatic or crural herniation of the ureter may also occur the ureter will display an unusual lateral and anterior course (Fig. 5.28). Retroperitoneal tumoral processes and genitourinary pelvic tumors may determine displacement and secondary obstruction of the ureters (Fig. 5.29). A distended bladder also induces ureteral and pyelocalyceal dilatation, and, therefore, the size of the collecting system must be controlled after micturition. In severe cases constipation may displace and distend the ureters... 

Severe morbidity has been reported after the use of regimens containing bleomycin 10% of patients developed adult respiratory distress syndrome and a further 9% needed prolonged ventilation (11). The authors thought that these rates were higher than expected and attributed this to a combination of the toxic effects of bleomycin on the lung and a large retroperitoneal and/or pulmonary tumor burden. 

Octreotide blocks the release of serotonin and many other active peptides and has been effective in controlling diarrhea and flushing. It is reported to have direct inhibitory effects on intestinal secretion and stimulatory effects on intestinal absorption. Non-gastrin-secreting adenomas of the pancreas are tumors associated with profuse watery diarrhea. This condition has been referred to as Verner-Morrison syndrome, WDHA (watery diarrhea, hypokalemia, and achlorhydria) syndrome, pancreatic cholera, watery diarrhea syndrome, and VIPoma. Excessive secretion of VIP from a retroperitoneal or pancreatic tumor produces most of the clinical features. Excessive VIP is isolated in about half of patients, along with numerous other peptide hormones (peptide histidine methionine [PHM], serotonin,... 

Radiographic imaging studies evaluate the extent of disease involvement. A chest x-ray should be performed to rule out the presence of metastatic spread to the lungs. A CT scan of the abdomen and pelvis is often performed to evaluate hepatic and retroperitoneal involvement and occult abdominal and pelvic disease, and to determine the depth of tumor penetration into the bowel wall and/or invasion to adjacent organs. Detection of lymph node involvement with either smdy is limited by the difficulty of distinguishing inflammatory or reactive lymph nodes from those infiltrated with tumor. Because CT scans may not adequately detect peritoneal seeding, small distant lymph node metastasis, or liver metastasis in colon cancer, an occasional patient may... 

The positive staining for AE1/AE3 and CAMS.2 that is seen in gastric carcinoids can help distinguish them from secondary involvement of the gastrointestinal tract by other neuroendocrine tumors such as pheochromocytoma and retroperitoneal paraganglioma. 

This entity can simulate a malignant tumor on radiographic studies and should be considered in children with other unusual problems such as retroperitoneal fibrosis, sclerosing cholangitis or in... 

The body phased-array coils available today allow imaging of the entire abdomen with high resolution and should be used whenever available to assess retroperitoneal lymph nodes in addition to evaluating the regional pelvic lymph nodes in all MRl examinations of a primary pelvic tumor. In patients with cervical or endometrial cancer, the demonstration of suspicious retroperitoneal lymph nodes is important for therapeutic planning in patients scheduled for postoperative radiotherapy. 

A number of genetic variations associated with disease are cited in Sect. 7.42.3 vide supra). A chromosome inversion was also seen in a family [2046], Testicular tumors in patients with P450 1 IB 1-related congenital adrenal hyperplasia showed functional features of adrenocortical tissues [2047], Hyperplasia of adrenal rest tissue was implicated in causing a retroperitoneal mass in a child withP450 llBl deficiency [2048],... 

These techniques also play an important role in evaluating the peri-lesional soft tissue and, particularly, the tumoral involvement of lymph nodes and retroperitoneal fat, corresponding to the retroportal pancreatic margin (Baek et al. 2001 Brugel et al. 2004). 

Fig. 21.5a-c. Axial oblique MPR (a) showing normal retroperitoneal fat, corresponding to the retroperitoneal pancreatic margin, next to the superior mesenteric artery in the coronal oblique MIP image (b) it is instead possible to appreciate an abnormal density of the fat tissue, suspected for microinfiltration the VR 3D image (c) shows the tumoral invasion of the retroperitoneum... 

Most renal masses can be characterized with high accuracy by noninvasive imaging alone, and a sohd non-fat-containing or complex renal mass should be considered a renal cell carcinoma until proven otherwise. Metas-tases to the kidney are usually small and multifocal or perinephric. Lymphomatous involvement of the kidneys also usually occurs in the setting of disseminated disease and is characterized by typical CT patterns like multiple small masses, spread from retroperitoneal disease, diffuse infiltration, and perinephric encasement. In a study by Lechevallier et al. (2000), CT-guided renal biopsy of 63 patients had an overall accuracy of 89%. Biopsy material was not sufficient for analysis in 15 patients (21%). Unsuccessful biopsy was related to lesion size biopsy was unsuccessful in 11 of 30 tumors (37%) of 3 cm or less, versus 4 of 43 (9%) of tumors greater than 3 cm. 

It is our firm conviction that CT-guided HDR brachytherapy features incontrovertible advantages, particularly when treating tumors that are large and close to blood vessels indeed the exact dosimetry that can be achieved allows protection of even adjacent structures from the effects of radiation. Accordingly, sensitive regions such as the retroperitoneal space, the mediastinal space or interloop locations are certainly accessible. 

Tumoral involvement Extrinsic compression Retroperitoneal fibrosis Constipation Megabladder Lithiasis... 

Fig. 24.10a,b. Retroperitoneal Wilms tumor rupture in a 9-year-old girl presenting with acute abdominal pain. Unenhanced CT scan (a) shows a perirenal hematoma (H). Enhanced CT (b) shows a subcapsular effusion related to tumor rupture (asterisk). Wilm s tumor (M)... 

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