Infection with multidrug-resistant Campylobacter coli mimicking recurrence of carcinoid syndrome: a case report of a neuroendocrine tumor patient with repeated diarrhea

Background: Campylobacteriosis caused by Gram-negative bacteria of the genus Campylobacter ( mainly C. jejuni and C. coli) is one of the most common gastrointestinal zoonotic infections with increased incidence in humans worldwide. The typical symptoms are severe abdominal cramps, diarrhea and sometimes fever. The clinical course of Campylobacter infection is mainly mild and after one week self-limiting, but can take several weeks in some rare cases. However, patients with neuroendocrine tumors in the gastrointestinal tract, a neoplasm of enterochromaffin/neuroendocrine cell origin, can develop severe diarrhea during progression of tumor growth caused by hormonal excess due to the tumor. Both diseases have very similar clinical symptoms and this case report elaborates the differences. So far it is known in the literature that the clinical symptoms of campylobacteriosis can mimic appendicitis or acute colitis of inflammatory bowel disease but a mimicking of recurrence of carcinoid syndrome in a patient with neuroendocrine tumor is not reported. Case presentation: A 72-year-old man with already diagnosed and treated metastatic neuroendocrine tumor of the terminal ileum (G1 rated, Ki-67 index 1 %) was again suffering from increasing diarrhea, abdominal cramps and weight lost. These symptoms were similar to the initial symptoms due to the tumor which improved at the time after total resection of the primary in the terminal ileum and regular therapy with long-acting release depot octreotide intramuscularly. As progression/tachyphylaxis in symptomatic patients with carcinoid syndrome undergoing therapy, reassessment of disease and analysis of tumor markers was initiated, and the interval of intramuscular injections was shortened. Radiological findings and tumor marker levels disclosed no evidence of neuroendocrine tumor progression and the symptoms continued. After 4 weeks with symptoms the patient developed additionally fever. Due to impaired renal function and elevated signs of systemic inflammation fluid replacement and empiric antimicrobial therapy were started. At this time-point the first stool cultures were taken which disclosed an infection with C. coli. The empiric antimicrobial therapy was stopped after five days because of multidrug-resistant isolated strain. During the ongoing symptomatic therapy the patient becomes gradually symptom-free 6 weeks later, resulting a total duration of symptoms caused by campylobacteriosis of 13 weeks. Conclusion: This case of infection with C. coli mimicking recurrence of carcinoid syndrome suggests that assessment for bacterial gastrointestinal infections should be taken into account also in patients with neuroendocrine tumors who present worsening of their symptoms in spite of initially successful management. The duration of symptoms caused by campylobacteriosis were significantly extended which might be due to gastroenteric dysfunctions/mucosal changes caused by the carcinoid syndrome in this patient.