The prevalence of small renal masses (SRM) has risen, paralleling the increased usage of cross-sectional imaging. A large proportion of these SRMs are not malignant, and do not require invasive treatment such as nephrectomy. Therefore, differentation between early renal cell carcinoma (RCC) and benign SRM is critical to achieve proper management. This article reviews the radiological features of benign SRMs, with focus on two of the most common benign entities, angiomyolipoma and oncocytoma, in terms of their common imaging findings and differential features from RCC. Furthermore, the role of percutaneous biopsy is discussed as imaging is yet imperfect, therefore necessitating biopsy in certain circumstances to confirm the benignity of SRMs.
Abdominal Fat/pathology ; Adenoma, Oxyphilic/diagnosis/radiography/ultrasonography ; Angiomyolipoma/diagnosis/radiography/ultrasonography ; Carcinoma, Renal Cell/*diagnosis/radiography/ultrasonography ; Diagnosis, Differential ; Humans ; Kidney Neoplasms/*diagnosis/*radiography/ultrasonography ; Leiomyoma/diagnosis/radiography/ultrasonography

OBJECTIVE: To evaluate the value of enhancement features and quantitative parameters of contrast-enhanced ultrasonography (CEUS) in differentiating solid hypoechoic renal angiomyolipomas (AMLs) from clear cell renal cell carcinomas (ccRCCs). MATERIALS AND METHODS: We analyzed the enhancement features and quantitative parameters of CEUS in 174 hypoechoic renal masses (32 AMLs and 142 ccRCCs) included in the study. RESULTS: Centripetal enhancement pattern was more common in AMLs than in ccRCCs on CEUS (71.9% vs. 23.2%, p < 0.001). At peak enhancement, all AMLs showed homogeneous enhancement (100% in AML, 27.5% in ccRCCs; p < 0.001). Quantitative analysis showed no significant difference between rise time and time to peak. Tumor-to-cortex (TOC) enhancement ratio in AMLs was significantly lower than that in ccRCCs (p < 0.001). The criteria of centripetal enhancement and homogeneous peak enhancement together with TOC ratio < 91.0% used to differentiate hypoechoic AMLs from ccRCCs resulted in a sensitivity and specificity of 68.9% and 95.8%, respectively. CONCLUSION: Both qualitative and quantitative analysis with CEUS are valuable in the differential diagnosis of hypoechoic renal AMLs from ccRCCs.
Adult ; Aged ; Angiomyolipoma/*diagnosis/pathology/*ultrasonography ; Carcinoma, Renal Cell/*diagnosis/pathology/*ultrasonography ; Contrast Media ; Diagnosis, Differential ; Female ; Humans ; Kidney Neoplasms/diagnosis/pathology/*ultrasonography ; Language ; Lipoma/ultrasonography ; Male ; Middle Aged ; Sensitivity and Specificity

OBJECTIVETo study the diagnosis and management of renal angiomyolipoma (RAML), and to identify risk factors affecting spontaneous angiomyolipoma rupture.

METHODSThe data of 68 patients with RAML from 1989 to 2002 were retrospectively reviewed. These patients were divided in two groups on the basis of tumor size, 35 patients in group A ( 4 cm).

RESULTSSeven patients were identified by image-guided percutaneous biopsy, and no major complications was noted. Sixteen patients with RAML were examined with angiography and 9 of 16 patients had got spontaneous rupture. 41.2% of patients were symptomatic, 4 cases (11.4%) in group A and 24 (72.7%) cases in group B (P < 0.01). There were significant differences in mean tumor size (11.6 cm +/- 5.1 cm vs 5.3 cm +/- 2.9 cm, P < 0.01) and mean aneurysm size (13.6 mm +/- 5.8 mm vs 2.6 mm +/- 3.0 mm, P < 0.01) between 9 cases of the ruptured tumor and 59 cases of unruptured tumor, 9 cases of the ruptured and 7 cases of unruptured tumor with angiography, respectively. Treatment consisted of conservative observation in 10 patients (no radiographic changes during the follow-up of 2 - 7 years); partial nephrectomy in 14 patients, tumor enucleation in 30 patients, total nephrectomy in 14 and posterior laparoscopic nephrectomy in 3 (no recurrence and complication correlation to operation during the follow-up of 2 - 144 months).

CONCLUSIONSIt is an important role that percutaneous biopsy guided by ultrasonography or computerized tomography performs in managing suspicious and/or indeterminate RAML. A higher probability of rupture is related to tumor and/or aneurysms size. Nephron-sparing surgery is the first choice for surgical treatment of RAML.

Adolescent ; Aged ; Angiomyolipoma ; diagnosis ; pathology ; therapy ; Biopsy, Needle ; Female ; Follow-Up Studies ; Humans ; Kidney Neoplasms ; diagnosis ; pathology ; therapy ; Male ; Middle Aged ; Nephrectomy ; methods ; Rupture, Spontaneous ; Tomography, X-Ray Computed ; Ultrasonography, Interventional

OBJECTIVEPancreatic metastasis from renal cell carcinoma (RCC) is a rare event and has not been reported in our country. We report a series of 3 patients with metastatic RCC to the pancreas after radical nephrectomy at our institution. The published reports in the literature were reviewed, and the diagnosis, treatment as well as prognosis of this rare event were discussed.

METHODSThe data of 3 RCC patients with metastasis to the pancreas were reviewed retrospectively, including radical nephrectomy, metastatic interval, the second and third surgical removal. Survival of the three patients was analyzed and the reports in the literature were compared as well.

RESULTSThe average interval from radical nephrectectomy to the comfirmed pancreatic metastasis was 6.6 years (range, 1.2 to 12 years). The pathological stage revealed T2N0M0 (n = 2) or T3N0M0 (n = 1), with right-sided tumor in 2 patients and left side in 1. One patient was asymptomatic, while the other two cases were symptomatic at presentation, including upper abdominal pain, weight loss, slight xanthochromia of the skin and titillation, clay stool (n = 1); irregular fever, weight loss and jaundice (n = 1). All pancreatic metastases were hypervascular on arterial stage of CT imaging. One patient had only a solitary pancreatic metastasis (n = 1), the another showed two metastatic lesions (n = 1), the third one had multiple lesions (n = 1). Surgical removal was accomplished in 2 patients: including pylorus-preserving pancreaticoduodenectomy in one, and pylorus-preserving pancreaticoduodenectomy together with partial tail resection in another one. The third one only received interventional therapy due to widespread extrapancreatic metastasis, and died of disseminated disease 11 months after the therapy. One of the above two surgically treated patients underwent the second removal due to local recurrence 2.5 years after the first removal of pancreatic metastasis. These two patients were still alive after follow-up of 8.6 years and 16.1 years, respectively.

CONCLUSIONRenal cell carcinoma is an unpredictable tumor that may demonstrate very delayed metastasis even from early-stage of the disease. The pancreas is a rare site of metastasis from renal cell carcinoma. We advocate careful long-term follow-up of patients with a history of RCC. Aggressive surgical management of pancreatic metastatic lesions may provide a chance of long-term survival.

Aged ; Carcinoma, Renal Cell ; pathology ; surgery ; Chemotherapy, Cancer, Regional Perfusion ; Female ; Follow-Up Studies ; Humans ; Kidney Neoplasms ; pathology ; surgery ; Male ; Middle Aged ; Neoplasm Recurrence, Local ; Neoplasm Staging ; Nephrectomy ; methods ; Pancreatic Neoplasms ; diagnosis ; drug therapy ; secondary ; surgery ; Pancreaticoduodenectomy ; methods ; Retrospective Studies ; Tomography, X-Ray Computed ; Ultrasonography, Doppler, Color