Imaging features of hereditary papillary renal cancers.

PURPOSE Our goal was to describe the imaging features of hereditary papillary renal cancer syndrome (HPRC), a new familial cancer syndrome. METHOD Members of seven kindreds with HPRC comprising 78 individuals were screened with contrast-enhanced CT and abdominal US. MRI was performed in three patients. Enhancement values and doubling times of solid masses were determined from CT scans. RESULTS Seventeen of 78 (22%) patients were affected. The HPRCs demonstrated lower enhancement (mean change in enhancement = 31 HU) than a comparable group of clear cell tumors (mean change in enhancement = 67 HU: p = 0.00001). The median tumor doubling time on serial CT was 18 months. The HPRCs were relatively hypovascular, enhanced uniformly, and grew slowly. Therefore, careful measurements of the region of interest should be obtained before and after intravenous administration of contrast medium. Though US detected only 45% of the lesions visualized on CT, it was useful in determining if lesions were cystic. Contrast-enhanced MRI demonstrated similar characteristics to contrast-enhanced CT. CONCLUSION The tumors of patients with HPRC pose some diagnostic difficulties because they can be missed by US, are small, and enhance poorly on CT. CT is preferable to US as a screening tool because of its higher sensitivity in detecting small lesions, and when contrast media cannot be administered, MR is a suitable alternative to CT.