Usefullness of EUS and EUS-FNAB for the metastatic pancreas cancers

Background & Aim: Though the metastatic lesions of the pancreas are rare, they represent a subtle cause of focal pancreatic lesions with difficulties in diagnosis by imaging alone. Also, reports described its EUS & EUS-FNAB findings were scarce. Hereby, we studied the effectiveness of EUS and EUS-FNAB utility for metastatic pancreatic lesions.

Methods: Over a 11-year period, a retrospective, single center study was designed to include all patients in the diagnosis of pancreatic metastases investigated with EUS and EUS-FNAB. EUS features were compared with those of primary pancreatic cancer as a control.

Results: Twenty-one patients underwent EUS, and 14 of them underwent EUS-FNA and/or 11 were operated. Primary lesions were renal cell cancer (6), lung cancer (4), sarcoma (3), malignant lymphoma (2), malignant melanoma (2), ovarian cancer (1), orbital cavity cancer (1), colon cancer (1), and breast cancer (1). Four patients discovered primary and metastatic site concurrently. Compared with control group, pancreatic metastases were more likely to be multiple, well-demarcated, heterogeneous (p=0.001) and with hallo-like low echoic margin (p=0.002). On the other hand, primary pancreatic cancers were more likely to have retention cyst (p=0.01), atrophic parenchyma at tail side (p=0.03). Tumor size, site, dilatation of MPD at tail side, calcification, and cystic degeneration had all no statistically significant difference. EUS-FNAB sampling adequacy obtained in 92.8% (13/14) and all were diagnosed as malignancy. Ten specimens were used immunohistochemichal stains and/or genetic test (k-ras) and it helped in suspected diagnosis. One case was false negative (insufficient sample) and it diagnosed as metastasis of renal cell cancer by surgery. There were no severe complications.

Conclusions: Pancreatic metastases are more likely to have multiple, well-demarcated, heterogeneous echo-pattern and hallo-like low echoic margin. EUS-FNAB for pancreatic metastases can have a decisive influence of appropriate therapeutic strategies.