Related Experiment Video
Updated: Nov 8, 2025
Assessing Urinary Tract Junction Obstruction Defects by Methylene Blue Dye Injection
Published on: October 12, 2017
Malakoplakia in the Urinary Bladder of 4 Puppies
Katelin L Davis1,2, Liang Cheng3, José Ramos-Vara1
1311308Purdue University, West Lafayette, IN, USA.
Abstract:
Malakoplakia in humans most often affects the urinary bladder and is characterized by inflammation with von Hansemann-type macrophages, with or without Michaelis-Gutmann bodies, and is frequently associated with Escherichia coli infection. We describe the microscopic features of malakoplakia in the urinary bladder of 4 puppies. In all cases, the lamina propria of the urinary bladder was markedly expanded by sheets of large, round to polygonal macrophages with intracytoplasmic, periodic acid-Schiff-positive granules and granular inclusions, and rare Prussian blue-positive inclusions. Macrophages were positive for CD18 and Iba1. In 2 cases, Michaelis-Gutmann bodies were detected with hematoxylin and eosin stain and were best demonstrated with von Kossa stain. E. coli infection was confirmed in 2 cases with bacterial culture or polymerase chain reaction (PCR) and sequencing of the bacterial 16S ribosomal RNA gene. Transmission electron microscopy of one case demonstrated macrophages with abundant lysosomes, phagolysosomes, and rod-shaped bacteria. Microscopic features were similar to human cases of malakoplakia. In dogs, the light microscopic characteristics of malakoplakia closely resemble granular cell tumors and histiocytic ulcerative colitis.
Insights
Malakoplakia, a rare inflammatory condition, was identified in four puppies' urinary bladders. Microscopic findings in these canine cases closely mirrored those observed in human malakoplakia.
Area of Science:
- Veterinary Pathology
- Canine Urology
- Immunopathology
Background:
- Malakoplakia is an inflammatory condition primarily affecting the human urinary bladder.
- It is characterized by specific macrophage types and often linked to Escherichia coli infections.
- Canine urinary bladder malakoplakia has not been well-documented.
Purpose of the Study:
- To describe the microscopic features of malakoplakia in the urinary bladders of four puppies.
- To compare canine malakoplakia findings with human cases.
- To differentiate canine malakoplakia from similar conditions like granular cell tumors.
Main Methods:
- Histopathological examination of urinary bladder tissues using Hematoxylin and Eosin (H&E) stain.
- Special stains including Periodic Acid-Schiff (PAS) and von Kossa stain.
- Immunohistochemistry for CD18 and Iba1 markers.
- Bacterial culture and Polymerase Chain Reaction (PCR) for Escherichia coli identification.
- Transmission electron microscopy (TEM) for ultrastructural analysis.
Main Results:
- All four puppies exhibited urinary bladder malakoplakia with characteristic von Hansemann-type macrophages containing intracytoplasmic inclusions.
- Michaelis-Gutmann bodies were identified in two cases.
- Escherichia coli infection was confirmed in two cases via culture or PCR.
- TEM revealed macrophages with lysosomes, phagolysosomes, and bacteria.
Conclusions:
- Canine urinary bladder malakoplakia shares microscopic similarities with human cases.
- Immunohistochemistry confirmed macrophage markers (CD18, Iba1).
- Microscopic features in dogs can resemble granular cell tumors and histiocytic ulcerative colitis, necessitating careful diagnosis.
Related Concept Videos
01:23Urinary Bladder
In males, the bladder is situated in front of the rectum, while in females, it is positioned anterior to the vagina and uterus. The bladder floor contains an inverted triangular area called the trigone, defined by the two ureteric...
01:19Anatomy of the Genitourinary System II: Bladder and Urethra
01:26Urinary Tract Calculi II: Pathophysiology and Clinical Manifestations
01:20Disorders of the Urinary System
Urinary tract infections (UTIs) are one of the most common urinary system disorders. They are caused by bacteria that enter the urethra and can spread to the bladder resulting in cystitis. Pyelonephritis is the result of a UTI that has ascended to the level of the...
01:09Cytoskeletal Linker Proteins - Plakins
01:51Lampbrush Chromosomes
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops...