JPC SYSTEMIC PATHOLOGY
DIGESTIVE SYSTEM
September 2018
D-F03

SIGNALMENT (JPC # 1632089):  An adult Vizsla dog

HISTORY:  This dog presented with intractable diarrhea unresponsive to therapy. 

HISTOPATHOLOGIC DESCRIPTION:  DF03a:  Colon:  Multifocally and transmurally, there are many extracellular and intrahistiocytic, round to oval, 8-20 um diameter algal sporangium that have a clear 2-4 um thick wall, and contain either central granular amphophilic material or multiple (2-8 or more) wedge-shaped endospores.  These are admixed with moderate numbers of macrophages and plasma cells, and rare lymphocytes and neutrophils that diffusely expand the lamina propria and extend through the muscularis mucosa and into the submucosa.  The submucosa is expanded up to twice normal thickness by algae and a similar population of inflammatory cells admixed with small amounts of hemorrhage and edema, and inflammation also mildly infiltrates the tunica muscularis, and multifocally disrupt serosa and attached mesentery.  Occasionally, the superficial mucosal epithelium is disrupted by eosinophilic cellular and karyorrhectic debris (necrosis) and the tunica muscularis has multifocal, mild myofiber degeneration and loss. 

DF03b: Colon (PAS): The algal cell wall is PAS positive. 

MORPHOLOGIC DIAGNOSIS:  Colon:  Colitis, histiocytic and plasmacytic, subacute, diffuse, moderate, with mesenteric steatitis and many extracellular and intrahistiocytic algae, Vizsla, canine.

ETIOLOGIC DIAGNOSIS:  Protothecal colitis

CAUSE:  Prototheca spp.   

GENERAL DISCUSSION: 

PATHOGENESIS: 

 

TYPICAL CLINICAL FINDINGS:

 

TYPICAL GROSS FINDINGS: 

 TYPICAL LIGHT MICROSCOPIC FINDINGS: 

ULTRASTRUCTURAL FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS: 

DIFFERENTIAL DIAGNOSIS:

Organisms that reproduce by endosporulation (mnemonic CRCB):

Granulomatous colitis in dogs:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Beribè F, Miglio A, Cassarani MP, Magi G, et al. What is your diagnosis? Systemic lymphadenopathy and blindness in a dog from Italy. Vet Clin Pathol. 2014; 43(4): 605-6.
  2. Cheville NF. Algae, fungi and other eukaryotes. In: Ultrastructural Pathology: The Comparative Cellular Basis of Disease. 2nd ed. Ames, IA: Wiley-Blackwell; 2009: 573-576.
  3. Gelberg HB. Alimentary System. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease.  6th ed. St. Louis, MO: Elsevier; 2017: 385-6.
  4. Greene CE, Rakich PM, Latimer KS. Protothecosis.  In:  Greene CE, ed. Infectious Diseases of the Dog and Cat. 4th ed. St. Louis, MO: Saunders; 2012: 696-701. 
  5. Huth N, Wenkel RF, Roschanski N, et al. Prototheca zopfii Genotype 2-induced Nasal Dermatitis in a Cat. J Comp Path. 2015; 152: 287-290.
  6. Moller A, Truyen U, Roesler U. Prototheca zopfii genotype 2-The causative agent of bovine protothecal mastitis?. Vet Microbiol. 2007;120(3-4):370-374.
  7. Schöniger S, Roschanski N, Rösler, et al. Prototheca species and Pithomyces chartarum as Causative Agents of Rhinitis and/or Sinusitis in Horses. J Comp Path. 2016; 155: 121-125.
  8. Uzal FA, Plattner BL, Hostetter JM. Alimentary System.  In: Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. 6th ed. Vol 2. St. Louis, MO:  Elsevier; 2016: 203-204.
  9. Vince AR, Pinard C, Ogilvie AT, et al. Protothecosis in a dog.  Can Vet J 2014; 55: 950-954.


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