MDCT findings of pancreatic metastases according to primary tumors.

Purpose: To describe the clinical and MDCT findings of metastatic pancreatic tumors (MPTs) from various primary malignancies and to determine whether there are characteristic imaging features of MPTs according to the various histologies of primary tumors.

Materials And Methods: Thirty-six patients with pathologically proven MPTs who underwent MDCT were retrospectively enrolled. Mean survival and factors associated with prolonged survival were analyzed using multivariate Cox regression analysis. MDCT was analyzed for the location, number, margin, and pattern and degree of enhancements of MPTs and main pancreatic duct (MPD) dilatations. Significant differences in CT features among the various histologies of MPTs were determined using the χ (2) or Fisher's exact test.

Results: The most common primary tumors metastasized to the pancreas were renal cell carcinomas (RCC) (n = 17), gastric cancers (n = 7), and colorectal cancers (n = 5). Mean survival was significantly different between RCC (106.7 months) and non-RCC (25.1 months) metastases (P < 0.001). A primary tumor of RCC was the only factor associated with prolonged survival (hazard ratio: 0.106, P = 0.003). On MDCT, pancreatic metastases from RCC were frequently multifocal, located at the center of the pancreas, usually homogeneous and well-defined with early wash-in and persistent enhancement; non-RCC metastases tended to be solitary, located off-center (P < 0.05), and appeared as heterogeneous, ill-defined nodules with persistent low attenuation (P < 0.05).

Conclusion: Various non-RCC tumors as well as RCCs metastasize to the pancreas but a primary tumor of RCC is the only factor associated with prolonged survival. MDCT features of MPTs are significantly different between the RCC and non-RCC metastases, potentially aiding in their differentiation and selection of the most appropriate management options for these patients.