Multiphasic enhancement patterns of small renal masses (≤4 cm) on preoperative computed tomography: Utility for distinguishing subtypes of renal cell carcinoma, angiomyolipoma, and oncocytoma

Phillip M. Pierorazio, Elias S. Hyams, Salina Tsai, Zhaoyong Feng, Bruce J. Trock, Jeffrey K. Mullins, Pamela T. Johnson, Elliot K. Fishman, Mohamad E. Allaf

Research output: Contribution to journalArticle

Abstract

Objective: To analyze the enhancement patterns of small renal masses (SRMs) during 4-phase computed tomography (CT) imaging to predict histology. Methods: One-hundred consecutive patients with SRMs and 4-phase preoperative CT imaging, who underwent extirpative surgery with a pathologic diagnosis of renal cell carcinoma (RCC), angiomyolipoma (AML), or oncocytoma, were identified from a single institution. An expert radiologist, blinded to histologic results, retrospectively recorded tumor size, RENAL (radius, exophytic/endophytic properties of the tumor, nearness of tumor deepest portion to the collecting system or sinus, anterior/posterior descriptor, and the location relative to polar lines) nephrometry score, tumor attenuation, and the renal cortex on all 4 acquisitions (precontrast, corticomedullary, nephrogenic, and delayed density). Results: Pathologic diagnoses included 48 clear-cell RCCs (ccRCCs), 22 papillary RCCs, 10 chromophobe RCCs, 13 oncocytomas, and 7 AMLs. There was no significant difference in median tumor size (P =.8), nephrometry score (P =.98), or anatomic location (P >.2) among histologies. Significant differences were noted in peak enhancement (P <.001) and phase-specific enhancement (P <.007) by histology. Papillary RCCs demonstrated a distinct enhancement pattern, with a peak Hounsfield unit (HU) of 56, and greatest enhancement during the NG and delayed phases. The highest peak HU were demonstrated by ccRCC (117 HU) and oncocytoma (125 HU); ccRCC more often peaked in the corticomedullary phase, whereas oncocytoma peaked in the nephrogenic phase. Conclusion: In a series of patients with SRMs undergoing 4-phase CT, tumor histologies demonstrated distinct enhancement patterns. Thus, preoperative 4-phase CT imaging may provide useful information regarding pathologic diagnosis in patients undergoing extirpative surgery.

Original languageEnglish (US)
Pages (from-to)1265-1272
Number of pages8
JournalUrology
Volume81
Issue number6
DOIs
StatePublished - Jun 2013

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ASJC Scopus subject areas

  • Urology

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