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.

Tumour Evolution and Seed and Soil Mechanism in Pancreatic Metastases of Renal Cell Carcinoma

“…In autopsy studies, the frequency is estimated at 1.6-11% [23][24][25][26]. Of 16,614 pancreatic operations due to malignancy listed in 16 clinical reports [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42], only 258 were performed for PM, resulting in a frequency of just 1.6%. Renal cell carcinoma (RCC), lung carcinomas, colorectal malignancies, melanomas, and sarcomas were reported as the most common primary malignancies [23,24,29,[43][44][45][46].…”

“…An interval of 9.6 (SD 6.8) years was calculated from 470 individually documented observations [28,[51][52][53]55]. In single institution reports [27,30,[32][33][34][39][40][41]44,47,, values from 5.3 [34] to 14 years [27] are documented (Table S1); the longest interval reported so far is 36 years [81]; (2) the frequent occurrence of multiple PM: Of 592 documented cases, 39.2% were multiple PM, with a mean of 3.1 pancreatic foci [82] and a maximum of 15 foci [28], and in large case compilations [27,30,[33][34][35]39,41,47,56,57,63,68,71,72,[75][76][77][78][79]83,84], values of 9% [71] to 70% [39] are given with a median of 36% (Table S2). (3) by favourable treatment results for metastasis surgery.…”

“…From 445 isPMRCC cases, a cumulative 5-year survival rate of 74.2% was calculated. In single institution reports [24,27,28,[30][31][32]34,35,39,[41][42][43][44][45][46][47]56,57,64,[66][67][68][69]71,[74][75][76]78,79,[83][84][85], values from 43% [78] to 100% [85] are presented with a median of 71%, and for the median overall survival following PM treatment, (OS) values from 3.4 [74] to 8.75 years [34], with a median of 6.2 years (Table S3) are reported. Further metastases after isPMRCC surgery [68] were observed in 124 [21,23,28,33,34,39,42,52,53,55,…”

“…Therefore, for years, authors who reported on this entity put up direct local metastatic pathway (MP) for discussion. This is on the one hand a local-lymphogenic MP after regional tumorous lymph node (LN) blockade [32,42,80,83,86,117,118] and on the other hand, a local venous MP via innate renoportal anastomoses [119] or via acquired draining collateral veins of hyper-vascularised tumours [32,42,80,83,86,87,117,118,120,121]. However, a high importance of these two MPs is countered by the fact that there are no reports of more frequent peripancreatic LN metastases in isPMRCC-that would be expected in lymphogenic tumour cell propagationnor are there more frequent postoperative liver metastases that would be expected to be associated with a high impact of reno-portal anastomosis in tumour cell spread.…”

“…However, a high importance of these two MPs is countered by the fact that there are no reports of more frequent peripancreatic LN metastases in isPMRCC-that would be expected in lymphogenic tumour cell propagationnor are there more frequent postoperative liver metastases that would be expected to be associated with a high impact of reno-portal anastomosis in tumour cell spread. For the frequency of peripancreatic LN metastases (Table S5), a value of 6.2% is calculated from 481 observations [28,30,32,35,41,43,56,57,68,69,71,73,75,76,84,88,122,123], and for the frequency of later liver metastases (Table S6) a value of 8.7% can be obtained from 288 observations documenting the postoperative outcome [21,28,33,34,42,70,80,84,87,[89][90][91][92][93][94]124]. These results attribute little if any importance to a local MP, whether lymphogenic or venous.…”