Microbiology & infectious diseases
Parasites-gastrointestinal (not liver)
Iodamoeba bütschlii
Author: Nat Pernick, M.D.
Last author update: 1 October 2018
Last staff update: 5 October 2020
Copyright: 2018-2024, PathologyOutlines.com, Inc.
PubMed Search: Iodamoeba bütschlii
Table of Contents
Definition / general | Terminology | Epidemiology | Sites | Etiology | Case reports | Cytology description | Cytology images | Differential diagnosisCite this page: Pernick N. Iodamoeba bütschlii. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/parasitologyiodamoebabutschlii.html. Accessed April 19th, 2024.
Definition / general
- Nonpathogenic ameba that can colonize the large intestine
Terminology
- The name Iodamoeba comes from the large clear space in the cytoplasm
Epidemiology
- One study found it more common in stool specimens from men who have sex with men (Diagn Cytopathol 2014;42:775)
Sites
- Reported as a fecal contaminant in anal and cervical Paps (Diagn Cytopathol 2014;42:775, Cytopathology 2010;21:342)
Etiology
- Acquired by ingesting contaminated food or water
- Does not appear to be associated with HIV infection
Case reports
- 46 year old man presented with untreated HIV and multifocal high grade SIL in a background of anal warts (Case of the Week #402)
- Man with cysts noted on rectal smear (Pritt: Creepy Dreadful Wonderful Parasites Blog - Case of the Week 512 [Accessed 24 October 2018])
- HIV+ man with Iodamoeba bütschlii in an anal Pap test confirmed by iodine stain (Diagn Cytopathol 2014;42:775)
Cytology description
- Small sized organisms (primarily amebic cysts and possibly trophozoites) between 5 - 20 microns in size (Pritt: Creepy Dreadful Wonderful Parasites Blog - Answer to Case 512 [Accessed 24 October 2018])
- Single nucleus with a large central karyosome, lack of peripheral chromatin and a small space between the karyosome and nuclear membrane (Pritt: Creepy Dreadful Wonderful Parasites Blog - Answer to Case 512 [Accessed 24 October 2018])
- Large cytoplasmic vacuole in the cytoplasm of the cyst form; prominent clear space in the cytoplasm is a glycogen mass that stains red-brown on iodine stain (Pritt: Creepy Dreadful Wonderful Parasites Blog - Answer to Case 512 [Accessed 24 October 2018])
Cytology images
Contributed by Bobbi Pritt, M.D.
Anal Pap smear
Case #402
Anal Pap smear
Differential diagnosis
- Entamoeba histolytica: similar size but its cytoplasm often contains ingested red blood cells and its nucleus has a smaller karyosome with a peripheral rim of condensed chromatin
- Endolimax nana and other nonpathogenic amebae: may be difficult to differentiate from I. bütschlii; requires a stool examination in the microbiology lab; nonpathogenic amebae can travel with pathogenic organisms (Diagn Cytopathol 2014;42:775)
