Cystic renal tumors: US and CT findings

Cystic renal tumors represent a variety of lesions in which both solid and liquid components coexist. These lesions may be either benign or malignant and include the multilocular cystic nephroma (MCN), the renal cell carcinoma (RCC), and the papillary adenocarcinoma (PAC). The MCN is a rare neoplasm formed of multiple loculated cystic masses divided by septa. The tumor is benign, although there are some rare reports of malignant cases. The RCC and the PAC may appear with cystic patterns. This is rather uncommon for the RCC, which inside has a unilocular or multilocular cystic appearance, if the necrotic component is large. PAC is an infrequent renal tumor, which has a greater tendency to appear as a large mass with a unilocular large cystic space. The ultrasonography (US) and computed tomographic (CT) features of 27 cystic tumors are presented. Both US and CT allowed the recognition of the cystic components, the septa, and the vegetations. The two imaging techniques made it possible to distinguish the tumors into “unilocular” and “multilocular” masses: the former correspond to RCC and PAC, the latter to MCN and RCC. CT added some information on calcified or partially calcified tumors. CT more than US enabled the differentiation between the malignant RCC and the benign MCN for which conservative surgery may be indicated. The two techniques did not allow the differentiation between RCC and PAC, which has different prognostic behavior.     

Bilateral renal lymphangiomatosis: US and CT findings

A case of bilateral renal lymphangiomatosis in an asymptomatic 50-year-old female is presented. Ultrasound and CT studies were performed. A finely septated fluid collection surrounding both kidneys and traversing the midline was found. Surgical biopsy was obtained and revealed findings compatible with lymphangiomatosis. A review of the literature of renal lymphangiomatosis is given. Received 24 October 1996; Revision received 10 February 1997; Accepted 11 March 1997     

Diagnostic value of MR imaging in comparison to CT in the detection and differential diagnosis of renal masses: ROC analysis

The aim of this work was to compare MR imaging and CT in the detection of renal masses and in the differential diagnosis between benign and malignant lesions. In 33 patients with 54 renal lesions CT and MR images were evaluated by four readers with regard to tumor detection and characterization using a receiver-operating-characteristics (ROC) analysis. The MRI protocol consisted of a T1-weighted spin-echo (SE) sequence (TR/TE: 300/10 ms) before and after contrast administration and a heavily T2-weighted turbo-SE (TSE) sequence (TR/TE: 5500/150 ms). A_z values for the area under the ROC curves for lesion detection were 0.92 ± 0.04 for CT and 0.91 ± 0.05 for MRI, respectively, which was not statistically different. The MRI technique was slightly, but not significantly, better than CT in the overall characterization (accuracy in differentiation between benign and malignant) of renal lesions with an A_z value of 0.90 ± 0.05 compared with 0.88 ± 0.06 for CT. The MRI technique proved to be statistically superior to CT (p < 0.01) in the correct characterization of benign renal lesions. MRI equals CT in the overall detection and differential diagnosis of renal masses. MRI is very helpful for further differential diagnosis of lesions which are equivocal on CT especially in the differentiation between complicated cysts and cystic or hypovascular renal cell carcinoma. Received 29 April 1996; Revision received 14 August 1996; Accepted 2 September 1996     

Nasopharyngeal teratoma: CT and MR findings

Teratomas of the nasopharynx occur usually in neonates. We present a case of teratoma which was discovered in an adult, and which relapsed after 34 years. The conventional radiograms, CT, MR, and histologic appearances are described. Received 3 January 1996; Revision received 1 March 1996; Accepted 4 March 1996     

Neurilemoma of the renal capsule: MR imaging and pathologic correlation

We report a case of neurilemoma arising from the renal capsule. Renal neurilemoma is an especially rare tumor, with only 15 cases previously reported. We attempted to correlate MR findings with microscopic components of the tumor. On T2-weighted images the solid part of the tumor was heterogeneous hyperintense. The MR signal intensity on T2-weighted images help estimate microscopic components of the renal neurilemoma.     

Renal trauma in occult ureteropelvic junction obstruction: CT findings

The aim of this study was to present CT findings of occult ureteropelvic junction obstruction in patients with renal trauma and to describe the clinical signs and singular CT features that are characteristically observed with trauma and are relevant to management of these patients. We retrospectively reviewed 82 helical CT studies in patients with renal trauma referred to our institution. We found 13 cases of occult preexisting renal pathology, six of which were occult ureteropelvic junction obstructions. The clinical presentation, radiologic findings of trauma according to the Federle classification, and CT findings of obstructed ureteropelvic junction are presented. We found three category-I lesions (one in a horseshoe kidney), two of them treated with nephrostomy because of increased ureteropelvic junction obstruction due to pelvic clots; two category-II lesions (parenchymal and renal pelvis lacerations) that had presented only with microhematuria; and one category-IV lesion (pelvic laceration alone). Pelvic extension was demonstrated in all the cases with perirenal collections. The CT studies in all the cases with suspected ureteropelvic junction obstruction showed decreased parenchymal thickness and enhancement, and dilatation of the renal pelvis and calyx, with a normal ureter. Computed tomography can provide information to confidently diagnose underlying ureteropelvic junction obstruction in renal trauma, categorize the traumatic injury (at times clinically silent) and facilitate proper management according to the singularities observed, such us rupture of the renal pelvis alone (Federle category IV) and increasing ureteropelvic obstruction due to clots which can be decompressed by nephrostomy. Received: 3 October 1997; Revision received: 6 April 1998; Accepted: 1 July 1998     

Multiple renal aspergillus abscesses in an AIDS patient: contrast-enhanced helical CT and MRI findings

Renal insufficiency or allergic reactions for X-ray contrast agents are frequent limitations in immunocompromised hosts such as neutropenic or AIDS patients. Due to a better tolerance of contrast agents in MRI, this technique is well suited for investigation of parenchymal organs. We demonstrate an allergic AIDS patient who presented with fever and flank pain. At sonography, anechoic renal lesions were supposed to be non-complicated cysts; however, on T2-weighted MRI, the center was of high signal. Dynamic contrast-enhanced MRI of the kidneys demonstrated an enhancing rim with ill-defined margins. The lesions were supposed to be multiple bilateral abscesses. Due to the multiple dynamic contrast series, a delayed enhancement of renal parenchyma was detectable adjacent to the lesion. This was suggested as accompanying local pyelonephritis and an infectious etiology became more reliable. Aspergillus fumigatus was identified by CT-guided biopsy as the underlying microorganism. The MR appearance of this manifestation has not been described previously. Received: 8 June 1998; Revision received: 7 August 1998; Accepted: 26 August 1998     

Imaging findings in renal hydatid disease

The aim of this work is to describe the image findings of renal hydatid disease, especially on MR. Four cases of echinococcal involvement of the kidney were retrospectively reviewed. All patients had intravenous urography (IVU) and US performed. Computed tomography examination was available in three patients and MR in two cases. Intravenous urography demonstrated communication of the cyst to the collecting system in one case. Ultrasound revealed multicystic appearance in three cases and unilocular in one case. Computed tomography demonstrated unilocular thick-walled or multilocular cysts with well-defined walls, calcified in one case. In multilocular cysts the CT densities of the fluid of daughter cysts was significantly lower than the fluid of mother cysts. This typical appearance was present in three of our cases. The presence of a hypointense rim and a multicystic appearance were distinctive in MR imaging. The combined findings of these different imaging modalities aid greatly in establishing the correct diagnosis. Magnetic resonance imaging is of value in determining the presence of a characteristic rim and enables the evaluation of anatomical relationships. Received 19 March 1996; Revision received 28 June 1996; Accepted 4 September 1996     

Foreign-body granuloma of the kidney: CT, MR and pathologic correlation

The differential diagnosis of renal masses containing fatty foci is limited to a small number of well-defined tumors, angiomyolipoma being the most frequent. In recent years clear cell carcinomas with intratumoral fatty foci have been reported, due to either entrapment of local fat or to regressive adipose metaplasia. Demonstration of focal calcifications is a valuable sign, being relatively common in carcinomas while rare in more benign lesions. We report a case of a foreign-body granuloma of the kidney, containing both calcifications and foci of fat. The value of this case, in our opinion, is that it demonstrates that detection of the previously mentioned features in a renal mass does not necessarily imply a presumptive diagnosis of renal cell carcinoma. Received: 11 June 1998; Revision received: 3 November 1998; Accepted: 23 November 1998     

Gas in the kidney: CT findings

Gas in the renal parenchyma is a rare finding seen best with computed tomography (CT). It can be encountered in a wide range of clinical conditions, some of them life-threatening like emphysematous pyelonephritis, whereas in others, it may represent a postoperative or procedure outcome. The latter are not usually a clinical emergency (for example, after nephrostomy insertion or in a urinary intestinal connection). Due to the increasing use of abdominal CT examinations, radiologists, especially in emergency setting, should be aware of this rare finding and be familiar with its differential diagnosis.     

Solid and papillary epithelial neoplasm of the pancreas: CT and MR findings

Solid and papillary epithelial neoplasm of the pancreas is a very rare low-grade malignant neoplasm with only 126 cases reported in the literature and seen mostly in young female patients. Surgical excision means cure in cases before malignant degeneration developed. Its characteristic findings are typical location in the tail of the pancreas, peripheral capsule formation, hypodensity on CT images, and hyperintense internal signal characteristics on T1-weighted MR images secondary to hemorrhage and accumulation of methemoglobine molecule. These findings are enough for the preoperative diagnosis that may lead to early surgery and cure. We present the CT and MR findings of this very rare neoplasm in a case report.     

Bouveret's syndrome: CT findings

Intestinal obstruction secondary to gallstones is seen in the older population and the level of obstruction is usually at the level of the terminal ileum. Obstruction at the level of the gastric outlet is called Bouveret's syndrome. A case with perforated cholecystitis and duodenal obstruction due to a gallstone is presented. The CT findings are presented along with the clinical findings and literature review. Received: 18 November 1999; Revised: 3 March 2000; Accepted: 14 March 2000     

Pulmonary lymphangioleiomyomatosis: high-resolution CT findings

Lymphangioleiomyomatosis (LAM) of the lung is a very rare disease. There are obvious discrepancies in the literature concerning the appearance of LAM on CT scans of the lung. This study adds the imaging findings of 11 patients and demonstrates how the imaging findings changed over time in four patients. Twenty-two CT examinations, and radiographs that had been obtained close to the CT examinations, of 11 patients with LAM confirmed by open lung biopsy were retrospectively evaluated with particular attention to the size of cystic lesions and wall thickness. Furthermore the CT scans were analysed for the type of pulmonary infiltration process and its distribution, presence or absence of pleural effusion, pneumothorax and lymph node enlargement. Clinical and CT follow-up studies were available in four patients. The CT scans revealed an increase in the interstitial pattern in all patients. Architectural distortion was seen in two patients and cystic lesions were present in all. The size of the cysts varied from small lesions to bullous emphysema. The cystic lesions revealed a wall thickness up to 2 mm but a wall was not perceptible in all. Pneumothorax was seen in only two patients; pleural effusion was seen in two patients. CT examination of patients with LAM reveals neither a uniform nor a pathognomonic appearance. In the early stages of LAM or in cases with interstitial changes the differential diagnosis of centrilobular emphysema or idiopathic pulmonary fibrosis seems to be more difficult than most authors believe. Received: 28 July 1997; Revision received: 20 October 1997; Accepted: 25 March 1998     

Renal replacement lipomatosis: ultrasonography and computed tomography findings

Replacement lipomatosis of the kidney is the result of severe atrophy or destruction of the renal parenchyma often caused by calculous disease with secondary marked proliferation of renal sinus, renal hilus, and perirenal fatty tissue. The diagnosis is difficult to establish with conventional radiographic methods. Although ultrasonography may show highly suggestive findings, computed tomography seems to be the most accurate method for demonstrating the distinctive features of replacement lipomatosis. Ultrasonographic and computed tomographic features in three cases of replacement lipomatosis of the kidney are reported. Received: 19 October 1998; Revision received: 8 December 1998; Accepted: 6 January 1999     

恶性骨肿瘤的CT诊断

目的：探讨恶性骨肿瘤的ＣＴ诊断及鉴别诊断。材料和方法：收集手术病理证实的３０例恶性骨肿瘤ＣＴ检查资料,分析其临床资料和ＣＴ表现。结果：ＣＴ易显示各类恶性骨肿瘤特征性表现,并对骨破坏、骨皮质破坏,软组织肿块、骨膜反应等能同时检出。结论：尽管各种恶性骨肿瘤均可表现骨破坏、骨膜反应、软组织肿块,但根据ＣＴ扫描的特点及表现,大多数肿瘤可作出正确诊断。     

Assessment of gastric cancer: value of breathhold technique and two-phase spiral CT

The purpose of this study was to evaluate the capabilities of subsecond spiral CT in detecting and staging of gastric cancer. Our study included 40 patients with endoscopically detected gastric carcinomas. Two-phase spiral CT was performed within one breathhold each. Distension of the stomach was achieved by intravenous application of scopolamine and drinking of 500 ml water. After bolus injection of contrast medium, scanning was performed in the arterial and venous phase. Gastric tumour extention and lymph node involvement was assessed. Gastric cancer was detected in 39 of 40 cases (sensitivity 97.5 %). Location of the tumour was correctly assessed in all cases. In 31 of the 39 cases (79.4 %) CT staging was accordant with pathological staging. One hundred two (70 %) of 145 nodes infiltrated by tumour tissue were detected and 144 (42.8 %) of 336 nodes free of metastatic involvement were found. The predictive values of positive and negative results for the detection of lymph node metastases were 67.1 and 75 %, respectively. Spiral CT is recommended for staging of gastric cancer. Received: 21 November 1997; Revision received: 9 March 1998; Accepted: 10 March 1998     

Exogenous lipoid pneumonia: high-resolution CT findings

The aim of this study was to assess high-resolution computed tomography (HRCT) findings of exogenous lipoid pneumonia. High-resolution computed tomography was obtained in 25 patients with proven exogenous lipoid pneumonia resulting from aspiration of squalene (derived from shark liver oil). Diagnosis was based on biopsy (n = 9), bronchoalveolar lavage (n = 8), or sputum cytology and clinical findings (n = 8). The clinical history of taking squalene was confirmed in all patients. The CT findings were classified into three patterns: diffuse ground-glass opacity, consolidation, and interstitial abnormalities. Distribution of the abnormalities, duration of taking squalene, predisposing factors for aspiration, and route of administration were analyzed. Ten patients showed diffuse ground-glass opacity pattern. Seven of 10 patients had predisposing conditions such as unconsciousness, pharyngeal dysmotility, or motor disturbances, and 6 patients had a recent history of taking large amount of squalene through nasal route. Seven patients who had consolidation pattern had a history of taking squalene for several months and did not have any predisposing factor. All of the 5 patients who had a pattern of interstitial abnormalities had a history of taking squalene longer than 1 year and showed segmental distribution of interstitial thickening with interposing ground-glass opacities. Three patients simultaneously had two different patterns at different lobes of the lung. The HRCT findings of lipoid pneumonia are ground-glass opacities, consolidation, and interstitial abnormalities. These HRCT findings with appropriate inquiries could be useful for diagnosis of exogeneous lipoid pneumonia. Received: 12 September 1997; Revision received: 13 February 1998; Accepted: 7 April 1998     

Calcific tendinitis of the gluteus maximus tendon: CT findings

Two cases of calcific tendinitis of gluteus maximus muscle are presented. The CT findings, including amorphous calcification without soft tissue mass and possible cortical erosion at the femoral enthesis of the gluteus maximus muscle, are highly suggestive of calcific tendinitis at this unusual but classical location. Ossifying entheses with well-defined cortical defect are frequent at the femoral insertion of the gluteus maximus muscle in asymptomatic subjects and must be differentiated from a real cortical erosion sometimes associated with these calcific tendinitis. Received: 16 July 1998; Revision received: 14 September 1998; Accepted: 13 October 1998     

Primary hepatic sarcomas: CT findings

Primary hepatic sarcomas are rare tumors that are difficult to diagnose clinically. Different primary hepatic sarcomas may have different clinical, morphologic, and radiological features. In this pictorial review, we summarized computed tomography (CT) findings of some relatively common types of hepatic sarcomas, including angiosarcoma, epithelioid hemangioendothelioma (EHE), liposarcoma, undifferentiated embryonal sarcoma (UES), leiomyosarcoma, malignant fibrous histiocytoma (MFH), and carcinosarcoma (including cystadenocarcinosarcoma). To our knowledge, hepatic cystadenocarcinosarcoma has not been described in the English literature. The CT findings in our case are similar to that of cystadenocarcinoma, a huge, multilocular cystic mass with a large mural nodule and solid portion. The advent of CT has allowed earlier detection of primary hepatic sarcomas as well as more accurate diagnosis and characterization. In addition, we briefly discuss the MRI findings and diagnostic value of primary hepatic sarcomas.     

儿童肾透明细胞肉瘤的增强CT诊断特征

目的：研究分析儿童肾透明细胞肉瘤（CCSK）的CT表现,以提高对此病的认识。方法：搜集本院2006年1月1日-2010年12月31日经手术病理结果证实的CCSK病例11例,其中男7例,女4例,年龄10个月-7岁,平均3.2岁。选取手术及化疗前的第一次CT检查为评价对象,对其进行临床分期和影像学分析。结果：肿瘤的术前临床和影像分期为Ⅰ期2例,Ⅱ期3例,Ⅲ期4例,Ⅳ期2例;瘤体大小10.2 cm×8.9 cm×7.9 cm,密度不均匀,所有肿瘤内均有不同程度的液化坏死灶,其中4例呈虎斑状条纹,6例可见钙化灶;增强扫描强化程度为（43.3±14.6）HU;8例瘤体内可见多发细小肿瘤血管;6例发生转移。结论：CCSK具有瘤体较大、易于坏死液化呈特征性的虎斑状条纹、钙化多见、血供丰富及早期发生多系统转移等CT特点,具有一定的诊断和鉴别诊断价值。