Differential diagnosis of complex cystic renal mass using multiphase computerized tomography

Area of Science:

• Radiology
• Urologic Oncology
• Medical Imaging

Background:

• Cystic renal masses require accurate differentiation between benign and malignant lesions.
• The Bosniak classification system is a standard tool for categorizing cystic renal masses.
• Multiphase computerized tomography (CT) is utilized in the evaluation of renal masses.

Purpose of the Study:

• To assess the added value of multiphase CT in improving the differential diagnosis of cystic renal masses using the Bosniak classification.
• To enhance diagnostic accuracy for differentiating renal cell carcinoma (RCC) in complex cystic renal masses.

Main Methods:

• A retrospective review of 104 patients with surgically managed Bosniak class II, III, and IV cystic renal masses (1997-2007).
• Preoperative multiphase CT enhancement differences (HU) between precontrast and corticomedullary phases were measured.
• Measurements were correlated with pathological findings to assess diagnostic performance.

Main Results:

• Renal cell carcinoma (RCC) was diagnosed in 53.8% of patients; clear cell histology was most common (62.5%).
• Significant differences in CT enhancement were observed between RCC and benign cysts, particularly in the corticomedullary phase (112.9 HU vs 59.8 HU).
• A corticomedullary phase minus precontrast phase value >42 HU demonstrated high sensitivity (97.1%) and specificity (85.7%) for differentiating RCC.

Conclusions:

• Combining Bosniak classification with multiphase CT enhancement differences significantly improves diagnostic accuracy for complex cystic renal masses.
• This combined approach aids in differentiating renal cell carcinoma and informs decisions regarding surgical intervention.
• Enhanced diagnostic capabilities can optimize the selection and methodology of surgical treatment for renal masses.