Pathological implications of areas of lower enhancement on contrast-enhanced computed tomography in renal-cell carcinoma: additional information for selecting candidates for surveillance protocols

Purpose Areas of lower enhancement on computed tomography are frequently seen in renal-cell carcinoma. We investigated whether tumor enhancement on the most prominent hypodense areas correlates with the nuclear grade and other pathologic variables. Methods From 2004 to 2009, all consecutive patients with a preoperative tomography who underwent radical or partial nephrectomy for renal-cell carcinoma at our tertiary referral center were retrospectively analyzed. Enhancement of the entire tumor on the slice with most prominent areas of lower enhancement was determined. Results Forty-eight patients were included. Clear-cell carcinoma comprised 91.6 %. Mean areas of lower enhancement for nuclear grade tumors 1–4 were 67.4, 38.7, 27.9, and 15.1 HU, respectively. Areas of lower enhancement negatively correlated with size, nuclear grade, T stage, and pathological stage. Tumors with extension beyond Gerota’s fascia (10.5 vs. 35.9 HU, p