Renal oncocytoma in a kidney transplant patient: the imaging features on contrast-enhanced ultrasonography (CEUS): a case report.

Renal oncocytoma is an infrequently reported renal neoplasm, often asymptomatic, which usually behaves as a benign entity and is identified accidentally on radiological imaging. Transplant patients under long-term immunosuppressive drugs have a high prevalence of cancers, such as skin cancers, lymphoproliferative disorders, and renal carcinomas. We present a case report of an asymptomatic renal oncocytoma in a kidney transplant recipient presenting persistent hematuria. The features of computed tomography and contrast-enhanced ultrasound (CEUS) are presented. This was the first time we used CEUS in a transplant kidney recipient presenting a renal mass, allowing the real-time visualization of contrast-enhancement patterns during all vascular phases for the differential diagnosis of renal tumors. Although the pattern of intense vascularization could mislead to an early judgment as a malignant lesion, it could help to exclude other renal lesions without inducing nephrotoxicity.

Renal oncocytoma in a kidney transplant patient: the imaging features on contrast-enhanced ultrasonography (CEUS): a case report / Oncocitoma renal em paciente transplantado: achados de imagem na ultrassonografia com contraste

Abstract Renal oncocytoma is an infrequently reported renal neoplasm, often asymptomatic, which usually behaves as a benign entity and is identified accidentally on radiological imaging. Transplant patients under long-term immunosuppressive drugs have a high prevalence of cancers, such as skin cancers, lymphoproliferative disorders, and renal carcinomas. We present a case report of an asymptomatic renal oncocytoma in a kidney transplant recipient presenting persistent hematuria. The features of computed tomography and contrast-enhanced ultrasound (CEUS) are presented. This was the first time we used CEUS in a transplant kidney recipient presenting a renal mass, allowing the real-time visualization of contrast-enhancement patterns during all vascular phases for the differential diagnosis of renal tumors. Although the pattern of intense vascularization could mislead to an early judgment as a malignant lesion, it could help to exclude other renal lesions without inducing nephrotoxicity.

Resumo O oncocitoma renal é uma neoplasia renal raramente relatada, muitas vezes assintomática, que geralmente se comporta como uma entidade benigna e é identificada acidentalmente em imagens radiológicas. Pacientes transplantados em regimes imunossupressores de longa duração apresentam alta prevalência de neoplasias tais como câncer de pele, distúrbios linfoproliferativos e carcinomas renais. Apresentamos o relato de um caso de oncocitoma renal assintomático em receptor de transplante renal com hematúria persistente. São apresentados os achados de imagens de tomografia computadorizada e ultrassonografia (US) com contraste. Foi a primeira vez que utilizamos a US com contraste em um receptor de transplante renal que apresentava massa renal, permitindo a visualização em tempo real dos padrões de realce do contraste em todas as fases vasculares para o diagnóstico diferencial dos tumores renais. Embora o padrão de vascularização intensa possa induzir uma avaliação precoce de lesão maligna, o exame ajuda a excluir outras lesões renais sem induzir nefrotoxicidade.

Multiple correspondence analysis in predictive logistic modelling: application to a living-donor kidney transplantation data.

This work deals with the use of multiple correspondence analysis (MCA) and a weighted Euclidean distance (the tolerance distance) as an exploratory tool in developing predictive logistic models. The method was applied to a living-donor kidney transplant data set with 109 cases and 13 predictors. This approach, followed by backward and forward selection procedures, yielded two models, one with four and another with two predictors. These models were compared to two other models, ordinarily built by backward and forward stepwise selection, which yielded, respectively, five and two predictors. After internal validation, the models performance statistics showed similar results. Likelihood ratio tests suggested that backward approach achieved a better fit than the forward modelling in both methods and the Vuong's non-nested test between backward-built models suggested that these were undistinguishable. We conclude that the tolerance distance, in combination with MCA, could be a feasible method for variable selection in logistic modelling, when there are several categorical predictors.

A heuristic index for selecting similar categories in multiple correspondence analysis applied to living donor kidney transplantation.

This work introduces a heuristic index (the "tolerance distance") to define the "closeness" of two variable categories in multiple correspondence analysis (MCA). This index is a weighted Euclidean distance where weightings are based on the "importance" of each MCA axis, and variable categories were considered to be associated when their distances were below the tolerance distance. This approach was applied to a renal transplantation data. The analysed variables were allograft survival and 13 of its putative predictors. A bootstrap-based stability analysis was employed for assessing result reliability. The method identified previously detected associations within the database, such as that between race of donors and recipients, and that between HLA match and Cyclosporine use. A hierarchical clustering algorithm was also applied to the same data, allowing for interpretations similar to those based on MCA. The defined tolerance distance could thus be used as an index of "closeness" in MCA, hence decreasing the subjectivity of interpreting MCA results.