RESUMO
Until now, few cases of coincidental giardiasis and pancreatic tumors have been described. Among these cases, three described giardiasis cases coincided with confirmed pancreatic cancer. We present another case of Giardia infection coexisting with pancreatic cancer in a 67-year-old man who suffered from stenosis of the distal ductus choledochus combined with a hypoechoic mass in the head of the pancreas. The diagnostic conclusion of suspicious adenocarcinoma was based on endoscopic ultrasound fine-needle aspiration (EUS-FNA) biopsy and confirmed by a partial duodenopancreatectomy. On bloody cytology smears prepared from the EUS-FNA specimen, trophozoites of Giardia intestinalis accompanying an inflammatory background and features that fulfilled the morphological criteria of malignancy were observed. In histological sections from the duodenopancreatectomy specimens, the parasites were observed attached to the epithelium, but individual Giardia parasites were also observed beneath the epithelial lining. According to conventional genotyping, the infecting Giardia belonged to sub-assemblage AII.