Small pancreatic cancer with giardiasis: a case report

Giardia lamblia Infection in a Duodenal Duplication Cyst as a Potential Cause of Recurrent Acute Pancreatitis

Giardia lamblia is a known etiological factor of a common infectious diarrhea. In rare cases, this parasite was found to be involved in the development of pancreatic and biliary tract diseases, both inflammatory and neoplastic. We present a case of a 64-year-old man known for a duodenal duplication cyst since 2013, with episodes of recurrent acute pancreatitis since 2017. He underwent endoscopic ultrasound-guided fine-needle aspiration of the duplication cyst, with evidence of G. lamblia infection. After treatment of giardiasis and evidence of parasite eradication, the episodes of recurrent acute pancreatitis ceased, following an ex adiuvantibus criterium.

Another case of coincidental Giardia infection and pancreatic cancer

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.

Extra-intestinal and long term consequences of Giardia duodenalis infections

Giardiasis is the most common waterborne parasitic infection of the human intestine worldwide. The etiological agent, Giardia duodenalis (syn. G. intestinalis, G. lamblia), is a flagellated, binucleated protozoan parasite which infects a wide array of mammalian hosts. Human giardiasis is a true cosmopolitan pathogen, with highest prevalence in developing countries. Giardiasis can present with a broad range of clinical manifestations from asymptomatic, to acute or chronic diarrheal disease associated with abdominal pain and nausea. Most infections are self-limiting, although re-infection and chronic infection can occur. Recent evidence indicating that Giardia may cause chronic post-infectious gastrointestinal complications have made it a topic of intense research. The causes of the post-infectious clinical manifestations due to Giardia, even after complete elimination of the parasite, remain obscure. This review offers a state-of-the-art discussion on the long-term consequences of Giardia infections, from extra-intestinal manifestations, growth and cognitive deficiencies, to post-infectious irritable bowel syndrome. The discussion also sheds light on some of the novel mechanisms recently implicated in the production of these post-infectious manifestations.

Gastrointestinal neoplasia associated with bowel parasitosis: real or imaginary?

Several parasitic species are well known to have carcinogenic properties, namely; Schistosoma hematobium (squamous cell carcinoma of the bladder) and the liver flukes Opisthorchis and Chlonorchis (cholangiocarcinoma). A large number of parasites are known to colonize the gastrointestinal tract. We sought to review the evidence that implicates these parasites in gastrointestinal neoplasia. Schistosoma japonicum, which is endemic primarily in east Asia, has been shown in multiple studies to convey a mildly increased risk of colorectal adenocarcinoma. The data supporting a causative role for Schistosoma mansoni in colorectal or other neoplastic processes are less convincing, limited primarily to small case-control studies and case series. Reports of possible associations between other gastrointestinal parasites (e.g., E. histolytica and A. lumbricoides) and neoplasia may be found in the literature but are limited to individual cases. We conclude that, other than S. japonicum and to a lesser extent S. mansoni, there is little evidence of an association between gastrointestinal parasites and neoplasia.