TY - JOUR
T1 - Giardia Is Often Overlooked on Histopathologic Examination
T2 - A High-Volume, Single-Institution Experience
AU - Shen, Minqian
AU - Voltaggio, Lysandra
AU - Robertson, Scott
N1 - Publisher Copyright:
© The Author(s) 2020.
PY - 2021/5
Y1 - 2021/5
N2 - 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.
AB - 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.
KW - Giardia lamblia
KW - duodenum
KW - immunodeficiency
KW - infection
KW - terminal ileum
UR - http://www.scopus.com/inward/record.url?scp=85089258754&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85089258754&partnerID=8YFLogxK
U2 - 10.1177/1066896920947795
DO - 10.1177/1066896920947795
M3 - Article
C2 - 32772760
AN - SCOPUS:85089258754
VL - 29
SP - 257
EP - 262
JO - International Journal of Surgical Pathology
JF - International Journal of Surgical Pathology
SN - 1066-8969
IS - 3
ER -