• DVM360_Conference_Charlotte,NC_banner
  • ACVCACVC
  • DVM 360
  • Fetch DVM 360Fetch DVM 360
DVM 360
dvm360 | Veterinary News, Veterinarian Insights, Medicine, Pet Care
dvm360 | Veterinary News, Veterinarian Insights, Medicine, Pet Care
By Role
AssociatesOwnersPractice ManagerStudentsTechnicians
Subscriptions
dvm360 Newsletterdvm360 Magazine
News
All News
Association
Breaking News
Education
Equine
FDA
Law & Ethics
Market Trends
Medical
Politics
Products
Recalls
Regulatory
Media
dvm360 LIVE!™
Expert Interviews
The Vet Blast Podcast
Medical World News
Pet Connections
The Dilemma Live
Vet Perspectives™
Weekly Newscast
dvm360 Insights™
Publications
All Publications
dvm360
Firstline
Supplements
Vetted
Clinical
All Clinical
Anesthesia
Animal Welfare
Behavior
Cardiology
CBD in Pets
Dentistry
Dermatology
Diabetes
Emergency & Critical Care
Endocrinology
Equine Medicine
Exotic Animal Medicine
Feline Medicine
Gastroenterology
Imaging
Infectious Diseases
Integrative Medicine
Nutrition
Oncology
Ophthalmology
Orthopedics
Pain Management
Parasitology
Surgery
Toxicology
Urology & Nephrology
Virtual Care
Business
All Business
Business & Personal Finance
Hospital Design
Personnel Management
Practice Finances
Practice Operations
Wellbeing & Lifestyle
Continuing Education
Conferences
Conference Listing
Conference Proceedings
Upcoming dvm360 Conferences
Resources
CBD in Pets
CE Requirements by State
Contests
Partners
Spotlight Series
Team Meeting in a Box
Toolkit
Top Recommended Veterinary Products
Vet to Vet
Veterinary Heroes
  • Contact Us
  • Fetch DVM360 Conference
  • Terms and Conditions
  • Privacy
  • Do Not Sell My Information
  • About Us

© 2023 MJH Life Sciences and dvm360 | Veterinary News, Veterinarian Insights, Medicine, Pet Care. All rights reserved.

Advertisement
By Role
  • Associates
  • Owners
  • Practice Manager
  • Students
  • Technicians
Subscriptions
  • dvm360 Newsletter
  • dvm360 Magazine
  • Contact Us
  • Fetch DVM360 Conference
  • Terms and Conditions
  • Privacy
  • Do Not Sell My Information
  • About Us
  • MJHLS Brand Logo

© 2023 MJH Life Sciences™ and dvm360 | Veterinary News, Veterinarian Insights, Medicine, Pet Care. All rights reserved.

Equine Image Quiz: A large, ulcerated abdominal lesion

December 29, 2016
Laura M. Riggs, DVM, PhD, DACVS-LA, DACVSMR

The itchy, growing wound also contains small, gritty masses. What is the most likely diagnosis?

Images courtesy of Laura M. Riggs, DVM, PhD, DACVS-LA, DACVSMR

You are asked to evaluate a large, ulcerated lesion on the ventral abdomen of a 10-year-old quarter horse mare. The owner reports that the rapidly growing mass is pruritic and that the horse has been seen rubbing and biting at the lesion. The lesion contains draining tracts from which you remove several small, gritty, tan masses. The mare has no other lesions, and the remainder of the physical examination is unremarkable. What is the most likely diagnosis in this horse?

A. Squamous cell carcinoma

B. Pythiosis

C. Sarcoidosis

D. Habronemiasis

Advertisement

 

If you chose B.) Pythiosis, you are correct!

Pythiosis is the term used for infection caused by the fungus-like microorganism Pythium insidiosum. The organism is primarily found in warm, humid regions like the southeastern United States, and infection occurs through small wounds or skin lesions. Horses that stand in lake water, swamps or flooded areas have an increased risk of infection, and lesions are most commonly found on the distal extremities and ventral abdomen. 

The lesions develop quickly and can become quite large in days to weeks. Unlike the other diagnoses listed, they are often pruritic, and self-induced trauma to the area is common. Another common finding is the presence of kunkers, or small, gritty, coral-like masses found within the ulcerated tissue. While these kunkers are not pathognomonic for Pythium insidiosum, their presence is highly suggestive of the organism.

As with any mass-like lesion, tissue samples should be submitted for histopathologic evaluation. However, histopathology results may only indicate granulomatous inflammation with or without hyphae, and special stains may be indicated to further differentiate the findings.

Definitive diagnosis of pythiosis is based on culture of the causative organism, but history, clinical signs and histopathology results are highly suggestive. Successful culture of the organism can be difficult. Culture of the kunkers found within the lesion is more often successful than culture of the surrounding tissue alone.

Treatment should be initiated as soon as pythiosis is suspected, as the prognosis for large or chronic lesions is poor. Successful resolution usually involves a combination of therapies, including aggressive surgical excision, antifungal administration (like amphotericin B) and immunotherapy. An immune-modulating “vaccine” has improved the prognosis, particularly in acute cases.

If identification and treatment are delayed, the lesions can quickly invade deeper structures, including tendons, ligaments, muscles and joints. Once these structures are involved, treatment becomes very difficult. Equine practitioners are advised to keep pythiosis on the differential list for lesions of this description.

Related Content:

Infectious DiseasesDermatologyEquine Medicine
Comparing treatments for restoring the skin barrier in atopic dogs
Comparing treatments for restoring the skin barrier in atopic dogs
Exploring molecular allergology as the future of allergy testing and immunotherapy
Exploring molecular allergology as the future of allergy testing and immunotherapy
dvm360® is seeking nominations for the 2023 Veterinary Heroes Awards
dvm360® is seeking nominations for the 2023 Veterinary Heroes Awards

Advertisement

Latest News

Meet the BlackDVM Network

Study finds certain canine breeds should be screened for cancer at young ages

AVMA releases 2 videos informing pet parents on pet dental care

Clinical research: the oral microbiome for earlier disease detection

View More Latest News
Advertisement