[Ultrasonography and computerized tomography in the evaluation of tumor invasion in renal adenocarcinoma].
BACKGROUND
Renal cell carcinoma, also known as renal adenocarcinoma is the most common primary renal malignancy. Protean and often nonspecific clinical manifestations of renal carcinoma have lead to its description as the "great imitator" in medicine. Because of the importance of early diagnosis and lack of specific clinical features, imaging has a vital role in its diagnosis. Since the only successful curative treatment of renal adenocarcinoma is surgery, preoperative evaluation of the extent of the disease may play an important role for determining surgical approach and tumor resectability. Over the past decade, computerized tomography has become the most widely used technique for staging renal adenocarcinoma, partly due to the very high overall accuracy of up to 90% that has been achieved. Ultrasonography is an effective, noninvasive and safe procedure that can be used as an initial method in patients suspected for renal adenocarcinoma.


METHODS
We studied 58 patients (24 females and 34 males, mean age 55.7 years) between 1995-1997 with a histologically confirmed diagnosis of renal adenocarcinoma. A total of 58 patients underwent radical nephrectomy for renal adenocarcinoma. Preoperatively. All patients were examined both by ultrasound and computerized tomography for various tumors characteristics, most commonly evaluation of tumor extension into perirenal structures and major veins invasion.


CONCLUSIONS
The sensitivity of computerized tomography was higher than that of ultrasonography for the demonstration of tumor extension into the perirenal structures (73.3% vs. 20%). CT does not demonstrate microscopic transcapsular spread of tumor. Criteria for perinephric invasion required a soft-tissue mass at least 1 cm in diameter in the perinephric space. False positive diagnoses do occur. This can be attributed to perinephric oedema, fat necrosis or fibrosis from remote inflammation which may simulate perinephric soft tissue nodules. For surgical planning it is important to determine whether the tumor extends into renal veins and inferior vena cava. Computerized tomography is better to study invasion of inferior vena cava than ultrasonography (100% vs. 66.6%). With regard to renal veins invasion both imaging procedures made false negative results, mainly ultrasonography. In relatively high proportion of cases overlying bowel gas precludes adequate visualization of the renal veins by ultrasonography.


CONCLUSIONS
Newer imaging modalities such as ultrasonography and computerized tomography have superseded conventional radiological methods in the diagnosis and evaluation of renal adenocarcinoma. Our results show that ultrasonography alone is unreliable in detecting tumor spread. Computerized tomography appears to be a more sensitive means of identifying tumor thrombus and tumor extension into perirenal structures. Perinephric tumor spread is the most difficult to detect but is of minor importance if radical nephrectomy is planned.
Pluzarev
O
O
Zavod za anatomiju, Medicinski fakultet, Novi Sad.
Budimlija
Z
Z
D002292:Carcinoma, Renal Cell / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography