Usefulness of multidetector computed tomography to differentiate between renal cell carcinoma and oncocytoma. A model validation

OBJECTIVE: The purpose of this study is to validate a multivariable predictive model previously developed to differentiate between renal cell carcinoma (RCC) and oncocytoma using CT parameters. METHODS AND MATERIALS: We included 100 renal lesions with final diagnosis of RCC or oncocytoma studied before surgery with 4-phase multidetector CT (MDCT). We evaluated the characteristics of the tumors and the enhancement patterns at baseline, arterial, nephrographic and excretory MDCT phases. RESULTS: Histopathologically 15 tumors were oncocytomas and 85 RCCs. RCCs were significantly larger (median 4.4 cm vs 2.8 cm, p = 0.006). There were significant differences in nodule attenuation in the excretory phase compared to baseline (median: 31 vs 42, p = 0.015), with RCCs having lower values. Heterogeneous enhancement patterns were also more frequent in RCCs (85.9% vs 60%, p = 0.027).Multivariable analysis showed that the independent predictors of malignancy were the enhancement pattern, with oncocytomas being more homogeneous in the nephrographic phase [Odds Ratio (OR) 0.16 (95% CI 0.03 to 0.75, p = 0.02)], nodule enhancement in the excretory phase compared to baseline, with RCCs showing lower enhancement [OR 0.96 (95% CI 0.93 to 0.99, p = 0.005)], and a size > 4 cm, with RCCs being larger [OR 5.89 (95% CI 1.10 to 31.58), p = 0.038]. CONCLUSION: The multivariable predictive model previously developed which combines different MDCT parameters, including lesion size > 4 cm, lesion enhancement in the excretory phase compared to baseline and enhancement heterogeneity, can be successfully applied to distinguish RCC from oncocytoma. ADVANCES IN KNOWLEDGE: This study confirms that multiparametric assessment using MDCT (including parameters such as size, homogeneity and enhancement differences between the excretory and the baseline phases) can help distinguish between RCCs and oncocytomas. While it is true that this multiparametric predictive model may not always correctly classify renal tumors such as RCC or oncocytoma, it can be used to determine which patients would benefit from pre-surgical biopsy to confirm that the tumor is in fact an oncocytoma, and thereby avoid unnecessary surgical treatments

Rol de la resonancia magnética renal en la monitorización del aclaramiento de los depósitos de hemosiderina en la hemoglobinuria paroxística nocturna

La hemoglobinuria paroxística nocturna (HPN) es un trastorno secundario a la deficiencia de CD55 y CD59, proteínas de superficie reguladoras del complemento, resultando en hemólisis crónica mediada por el complemento1. La afectación renal oscila entre la lesión renal aguda durante las crisis hemolíticas, la disfunción tubular proximal (DTP) y la enfermedad renal crónica (ERC)2. La hemoglobinuria solo ocurre en el 25% de los pacientes3, en series recientes se ha reportado una incidencia del 64% de ERC, con hasta un 20% de ERC estadio 3-54. Se presentan 2 casos de HPN en el que los depósitos de hemosiderina visualizadas por resonancia magnética (IRM) parecen ser los primeros signos de afectación renal