Among cancers occurring in the pancreas, metastatic lesions are uncommon comprising approximately 2% of all pancreatic malignancies (1-2). Most frequent origin of the metastatic cancers is the kidney. From the urologist’s standpoint, metastatic renal cell carcinoma (mRCC) to the pancreas has several unique characteristics. They typically occur after a long disease-free period following an initial curative resection, most commonly a nephrectomy or partial nephrectomy. Among the histologic subtypes of RCC, invariably clear cell RCC is observed to metastasize to pancreas, the subtype associated with the von Hippel-Lindau disease. Frequently, pancreas is the only metastatic site and they respond exceedingly well to complete surgical resection in amenable cases resulting in good prognoses.
Radiographically, mRCC in the pancreas resembles endocrine pancreatic neoplasms and the differentiation between hypervascular mRCC and nonfunctioning neuroendocrine tumors is known to be difficult. Invariably, the CT characteristics of the pancreatic mRCC are very similar to the primary RCC, with well-defined margins and strong enhancement greater than the normal pancreas especially at the rim during the arterial phase (4). Location of the pancreatic mRCC is variable, equally dispersed between head, body and the tail. However, an observational study suggested site-specific occurrence. Among metastases involving the head, neck and the uncinate process 62% were from the right kidney while of the metastases involving the body and the tail, 29% were from the right kidney (5).
The recognition that pancreatic metastasectomy is associated with a high rate of mortality and morbidity has changed over the past several decades. More contemporary series suggest a perioperative mortality rate of 2% and a morbidity rate of 38 to 48%. Most complications were Clavien grade I (62%), and grade IV complication was reported in 6-8% (4-6). Rewarding is the prognoses after the surgery in mRCC patients, as the patients after complete metastasectomy benefit from a median 3.7 years of recurrence-free period (2). In a pooled analysis, median overall survival was estimated at 8.7 years and a 5-year survival of 66%. In the era of tyrosine-kinase inhibitors, the beneficial role of pancreatic metastasectomy is questioned again (7). Nonetheless, indolent clinical course, potential for postponing systemic therapy during the disease-free period coupled with surgical advancement make pancreatic metastasectomy in carefully selected patients one of the most powerful armamentarium in the management of mRCC patients.