Pararenal pseudotumors of the diaphragm: computed tomographic features.

Two cases of diaphragmatic pseudotumors in the right posterolateral pararenal space are reported to highlight their unusual location and their confusing computed tomographic pattern.

CT features of perirectal fascia thickening after transurethral resection of prostatic adenoma.

Thickening of the perirectal fascia (PRF) has been described as a CT sign of local extension of pelvic cancers. It has been observed also after radiation therapy and various pelvic surgical procedures. To demonstrate prospectively its nonspecificity, we systematically looked for such thickening before and after consecutive uneventful transurethral prostatic resections in 17 patients presenting with benign adenomas and in one patient with an unexpected prostatic carcinoma. In six patients (33%) obvious PRF thickening appeared on postoperative CT. Thus, this cause of fascial thickening must be considered when evaluating pelvic cancers.

Cystic renal cancers: CT characteristics.

The preoperative distinction between renal cyst and tumor has long been a dilemma. A cystic renal adenocarcinoma may appear similar to a largely necrotic tumor or a cancer incorporated into a cyst or arising from a cyst wall. Overall, these cystic cancers present the same preoperative features. In our series of 15 cases, the characteristic pattern on computed tomography scans included size greater than or equal to 10 cm, localized thickening of cyst walls with contrast enhancement, and irregularly and poorly defined implantation in the kidney.

Local recurrence after nephrectomy for primary renal cancer: computerized tomography recognition.

We diagnosed by computerized tomography 15 local recurrences in 88 patients who had undergone nephrectomy for renal cancer, with no false positives and 1 false negative. This over-all low rate (17 per cent) probably is owing to the fact that computerized tomography scans were done in patients in good clinical condition. Local recurrence was noted in 3 of 59 asymptomatic patients and in 12 of 19 patients with local symptoms. No recurrence was noted in 10 patients with general symptoms. Thus, 20 per cent of local recurrences were asymptomatic and 80 per cent presented with local symptoms. High local recurrence rates were found in cases of transitional cell carcinoma with whole wall involvement or extension to adjacent tissues (4 of 8 patients, 50 per cent), clear cell adenocarcinoma with lymph node involvement (3 of 7 patients, 43 per cent) and partial nephrectomy (3 of 6 patients, 50 per cent). Therefore, we consider such patients to be at high risk. Our study demonstrates that computerized tomography enables earlier, accurate diagnosis of smaller local recurrence in asymptomatic patients and provides a sensitive, reliable, noninvasive, repetitive method of evaluation of clinical treatment trials. Routine followup should be reserved for high risk patients.

Pseudotumoral ureteral kinking: a computed tomography pitfall.

On computed tomography, the kinking of a large ureter may falsely suggest an ureteral tumor. This pitfall likely correlates with the intraluminal protrusion of the ureteral wall folds.

Transformation of a pericardial cyst observed on long-term follow-up.

An atypical pattern of pericardial cyst was observed on a routine chest radiograph of a healthy 25-year-old woman. It appeared as an important elevation of the right diaphragm. The cystic nature of the mass was easily disclosed by ultrasonography and computed tomography, but its location--thoracic, diaphragmatic, or subphrenic--remained questionable. Finally, a percutaneous puncture yielded 1300 mL of clear liquid. Despite this huge volume, the cyst had been asymptomatic and did not recur after complete aspiration. Retrospectively, owing to previous files, we could recognize the evolution of a pericardial cyst from the age of 13 years. At that time, it was much smaller and was evaluated by a series of aggressive investigations, although it had a more typical pattern and was confined to the right cardiophrenic angle.

Radiological evaluation of the peri- and pararenal spaces by computed tomography.

Computed tomography (CT) gives an excellent opportunity to revisit normal anatomy and to understand pathological aspects. Renal fascia alterations, on CT scans, are a sensitive sign of local lesion. While a thin renal fascia has no pathological significance, any thickening may be considered abnormal although nonspecific. It is found in pancreatitis as well as in cancer of the pancreas, in renal tumors as well as in pyelonephritis. It may persist as a scar. On the other hand, lack of fascial thickening allows us to rule out renal extension of a neighboring lesion or to decide that a renal mass is an ancient slowly-growing benign one.

Computed tomography versus aortography in diagnosis of aortic dissection.

The use of computed tomography (CT) versus aortography is evaluated in a limited study of 17 cases of aortic dissection (AD). With the constraints of the present state of the technology and lack of availability of CT scanners at some centers, aortography remains the premier and often the only diagnostic test to choose in an emergency. CT, however, may be an asset in the diagnosis of AD when: (1) atypical or misleading clinical presentations are evident that do not require aortography; (2) aortography is contraindicated in a weakened patient, when there is no emergency; (3) aortography is a risk while there is a strong suggestion of AD; (4) patency of a false channel must be confirmed. These circumstances were encountered in five patients. In addition, a localized infrarenal AD was fortuitously discovered in two patients presenting with abdominal visceral cancer. On patient follow-up, CT is less invasive and may be performed in asymptomatic patients undergoing treatment, thereby facilitating the early detection of complications. Detailed computed tomograms often yield superior diagnostic information only if the CT study includes rapid sequential scans immediately following a fast intravenous bolus of contrast material.

Computed tomography of multilocular cystic nephroma.

Three cases of multilocular cystic nephroma (MNC) tht were demonstrated by computed tomography (CT) are described. In two cases a correct preoperative diagnosis was made. In the third case, however, the mass did not fit exactly the histologic criteria for MCN. MCN appears on CT scans as a well-marginated, rounded, or polycyclic cortical mass that extends beyond the normal renal outline. This mass contains cysts that vary in size and number. It may be a cluster of a few large cysts with thick walls and septa, or it may be a denser mass composed of tiny cysts. This CT pattern is suggestive of MCN, but is not sufficient to obviate surgery. However, as part of a complete preoperative evaluation including arteriography, CT provides information that may be valuable in limiting the surgical procedure, perhaps avoiding unnecessary nephrectomy.

Visibility and thickening of the renal fascia on computed tomograms.

The renal fascia can be seen on CT scans (using appropriate window settings) in most patients except those with very little fat. CT confirms current anatomical concepts; however, contrary to the illustrations shown in the literature, it clearly demonstrates that the anterior pararenal space normally exists only at the level of the retroperitoneal organs. A lesion would distend the space. While visualization of the renal fascia on normal urograms may be an indication of renal disease, a thin renal fascia on CT scans has no pathological significance. Thickening is nonspecific: it is not pathognomonic of tumor, nor is it helpful in differentiating pancreatitis from neoplasm. On the other hand, lack of fascial thickening may be helpful in ruling out renal extension of a neighboring lesion.

Cystadenomas of the pancreas: diagnosis by computed tomography.

Three cases of benign pancreatic cystadenoma, diagnosed by computed tomography (CT), are reported. Other neoplasms with similar CT appearance are illustrated as examples of some pitfalls in the CT diagnosis of cystadenoma.

Computed tomography of the gastrointestinal tract: lesion recognition and pitfalls.

Abnormalities in the gastrointestinal tract will be found on computed tomography (CT) scans performed for other indications if they are carefully searched for. This potential will increase as CT is used earlier in the investigation of suspected abnormalities of the pancreas. retroperitoneum, and liver. Additionally, CT may be valuable in assessing the extent of a known primary lesion of the alimentary tract.