Histopathological Aspects of Pancreatic Metastases in Renal Cell Carcinoma: Does the Mode of Invasion Permit Limited Resections?

Abstract

Purpose: To investigate histopathological characteristics, we retrospectively analyzed data from patients who underwent resection of renal cell carcinoma pancreatic metastases (RCC-PMs). Methods: This study included 34 RCC-PM lesions in 13 patients who underwent 15 pancreatic operations. The clinicopathlogical characteristics were analyzed with special emphasis on tumor capsular formation, manner of peritumoral invasion, and presence of lymphovascular invasion. Results: Median duration to onset of RCC-PMs was 101 months from initial nephrectomy. Surgical procedures included distal pancreatectomy in 6 cases, pancreaticoduodenectomy in 4, total pancreatectomy in 1, and limited resections in 6 with two overlapping procedures. No perioperative deaths were encountered. One, three, and five year survival rates after pancreatic resection were 86.2%, 86.2%, and 76.6%, respectively. Of thirty- four lesions 32 lesions with tumor diameter ≤ 35 mm were encapsulated. Of these 32 lesions with capsule formation, extra capsular invasion was identified in 5 lesions. No lymphatic invasion was identified in any case. Venous invasion was presented just adjacent to the tumors in 2 lesions. Five year survival rates for the 11 cases with standard operations and 4 cases with limited resection were 70.7% and 100%, respectively without any significant difference. Conclusions: Small RCC-PMs were frequently encapsulated, seldom invaded into pancreatic parenchyma, and were rarely accompanied by microscopic lymph vascular invasion. Limited resection of the pancreas with adequate surgical margins may be oncologically acceptable.