Low enhancing papillary renal cell carcinoma diagnosed by using dual energy computerized tomography: a case report and review of literature

BACKGROUND Papillary renal cell carcinoma (pRCC) is a mixed group of tumors that constitutes about 15-20% of all renal cortical cancers. Strong enhancement on computerized tomography (CT) is a feature of clear cell, but not of pRCC making the differentiation of papillary tumors from benign cysts a diagnostic problem in some cases. CASE PRESENTATION We report here a case of a female patient with pRCC that was initially diagnosed as a benign renal cyst. The patient is a 66 year old Caucasian female who initially presented with an ultrasound showing a 2.6 cm hypo-echoic lesion within the inferior pole of her left kidney. This was followed by a contrast enhanced computerized tomography that suggested the hypo-echoic lesion to be a hyper-attenuating benign renal cyst. Follow-up CT scan 4 months later demonstrated an increase in the size of the lesion to 3.2 cm with equivocal enhancement. A dual energy computerized tomography (DECT) showed the lesion to be a solid mass suspicious for renal cell carcinoma. A robotic partial nephrectomy revealed a papillary renal cell carcinoma with negative margins. CONCLUSION In this case report, we reviewed the literature on variations in enhancement of renal tumors and the possible role of dual energy contract enhanced CT in differentiating papillary tumors with low enhancement from benign kidney cystic lesions.