Background Atypical and suspicious cytology results are not uncommon in Endoscopic Ultrasound Guided - Fine Needle Aspiration. Few reports have assessed the true risk of malignancy for these indeterminate categories. Atypical and suspicious categories do not have standard criteria and may vary depending on pathologist and institute. The aim of this study was to determine the long term follow-up and risk of malignancy in patients with atypical or suspicious cytology. Methods 1215 consecutive inpatient and outpatient endoscopic ultrasound guided - fine needle aspirations performed at a single academic tertiary care center from 10/21/2009-12/31/2013 were reviewed. Patients with solid pancreas mass lesions who had suspicious or atypical final cytology were identified for further clinical outcome analysis. The primary end point was the risk of having a subsequent diagnosis of malignancy. Results Of the 1215 patients with pancreas mass lesions, 45(3.7%) were given an indeterminate final cytologic diagnosis with 23 atypical and 22 suspicious for malignancy. Of the 19 patients with follow-up with atypical cytology, 13(68%) had subsequent diagnosis of malignancy. In the suspicious cytology group with follow-up, 18 of 20 patients (90%) after the index procedure had a subsequent diagnosis of malignancy. Conclusion The risk of subsequent malignancy is high for both atypical and suspicious pancreatic solid lesions. Management of patients with indeterminate cytology results should involve a multidisciplinary team and also incorporate the clinical and imaging features of the case. Depending on these features, repeat endoscopic ultrasound guided - fine needle aspiration should be considered for atypical cytology. Surgical resection of suspicious lesions may be warranted given the high risk of subsequent malignancy in this group. Further research is needed to know the true risk of malignancy in indeterminate cytology groups. Risk may vary depending on institute and pathologist interpretation.
Eric M Nelsen, Jeffrey Hubers, Patrick R Pfau, Deepak V Gopal, Mark E Benson