A case of congenital capillary proliferation of the kidney (CCPK)

We report a case of congenital capillary proliferation of the kidney (CCPK) along with the multimodality imaging findings. Four-day-old boy who had managed due to his mother's gestational diabetes underwent abdominal ultrasound and a mass was detected in the right kidney. On gray scale ultrasound, the mass exhibited a hyperechoic, slight lobulated shape and a circumscribed margin. On Doppler mode, the mass showed hypervascularity in its peripheral to central zones. On MRI, the mass was hyperintense on the T2-weighted image, and no diffusion restriction was noted on DWI/ADC. On computed tomography, strong enhancement was shown at center of the mass at the post-contrast early phase; homogeneous enhancement at the entirety of the mass was observed at the delayed phase. We suspected hemangioma but did not rule out the possibility of malignancy. Surgery was performed. Pathologically, the specimen showed a proliferation of capillaries which were positive for vascular endothelial markers and negative for GLUT1 in immunohistochemistry. A small number of entrapped tubules and glomeruli were also observed. After an intensive pathological examination, the diagnosis of CCPK was finally considered. CCPK was recently described as an extremely rare childhood renal vascular lesion, and to our knowledge, only five other cases have been reported. Our patient's multimodality imaging findings well reflected the characteristics of a vascular lesion.