Giardia Is Often Overlooked on Histopathologic Examination: A High-Volume, Single-Institution Experience

Minqian Shen, Lysandra Voltaggio, Scott Robertson

Research output: Contribution to journalArticlepeer-review

Abstract

Aims. Giardia: is sometimes missed by the pathologist, and we sought to determine how often this occurs at our institution—a large tertiary care center with a subspecialty gastrointestinal pathology service and what certain clinical and histologic clues can be used to flag cases with a higher likelihood of infection, targeting them for greater scrutiny. Methods and Results: We identified a set of patients who tested positive for Giardia with a stool-based test, and who also received a small bowel biopsy at a similar time-point. These biopsies were retrospectively reviewed for Giardia, finding 8 positive cases. The organism was prospectively detected in 4 cases (50%) but overlooked in the remaining 4 cases (50%). Three of the 4 cases missed cases showed only rare organisms. The detected cases tended to more frequently have prominent lymphoid aggregates (3 detected cases, 0 overlooked cases) and intraepithelial lymphocytosis (3 detected cases, 0 overlooked cases). Certain clinical and histologic clues can be used to flag cases with a higher likelihood of infection. Specifically, we found abnormalities of the mucosa (active inflammation, intraepithelial lymphocytosis, villous expansion, prominent lymphoid aggregates) in each case, and 4 of 8 cases were from immunocompromised patients. Finally, 2 of 8 cases were terminal ileum biopsies. Conclusions: Biopsies with a histologic abnormality or those from immunocompromised patients should receive greater attention. Routinely looking for Giardia at that terminal ileum is necessary.

Original languageEnglish (US)
JournalInternational journal of surgical pathology
DOIs
StateAccepted/In press - 2020

Keywords

  • duodenum
  • Giardia lamblia
  • immunodeficiency
  • infection
  • terminal ileum

ASJC Scopus subject areas

  • Anatomy
  • Surgery
  • Pathology and Forensic Medicine

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