Endocrine Abstracts

Background: Organ infiltration and metastasis are the only parameters defining malignancy of pancreatic endocrine tumors. Several studies had demonstrated the prognostic value of Ki-67 expression measured on histological sections obtained from the removed pancreatic endocrine tumors. We postulate that Ki-67 expression measured on fine needle aspiration cytology provides pre-operative indications of the malignancy of pancreatic endocrine tumors.

Aim: Aims of this study were: 1) to examine the feasibility of measuring expression of Ki-67 on fine needle aspiration cytology; and 2) to compare the measurements of Ki-67 expression obtained on fine needle aspiration cytology and histological sections from the removed tumor.

Methods: We measured Ki-67 expression on endoscopic ultrasonography fine needle aspiration cytology performed for diagnostic purposes and histological sections obtained after surgical removal of the tumor in ten patients with pancreatic endocrine tumors.

Results: Adequate aspirate volumes were available on 6 out of 10 patients. Expression of Ki-67 was 20%, 15%, 1%, <1%, 1–2%, <1% in cytology and 15%, 19%, <1%, <1%, 2%, <1% in histology, respectively.

Conclusions: The results of this pilot study suggest that measurement of Ki-67 expression is feasible on fine needle aspiration cytology and there is a good category agreement of Ki-67 expression between endoscopic ultrasonography fine needle aspiration cytology and histological sections of the tumor. If our results are confirmed in a larger study, Ki-67 expression on cytology may help to discriminate between low and medium/high proliferative tumors and used for prognostic and therapeutic pre-operative evaluation of endocrine pancreatic tumors.