JPC SYSTEMIC PATHOLOGY

INTEGUMENTARY SYSTEM

November 2016

I-P01

 

Signalment (JPC # 1823588):  Age and breed unspecified, horse

HISTORY:  This horse had generalized dermatitis.  Several randomly scattered nodular cutaneous lesions were also present in and around the cervical region

MICROSCOPIC DESCRIPTION:  Haired skin, site not specified:  Within the superficial and deep dermis, predominantly surrounding blood vessels and adnexa, there are variably sized, nodular, aggregates of high numbers of eosinophils, fewer lymphocytes, plasma cells, mast cells, and occasional melanomacrophages (pigmentary incontinence).  There are numerous tangential and longitudinal sections of 3-4um wide microfilaria scattered throughout areas of dermal inflammation.  The overlying epidermis is mildly hyperplastic with mild orthokeratotic hyperkeratosis.

MORPHOLOGIC DIAGNOSIS:  Haired skin, site not specified:  Dermatitis, perivascular and periadnexal, eosinophilic, subacute, multifocal, moderate, with numerous microfilariae, breed unspecified, equine

ETIOLOGY:  Onchocerca cervicalis

ETIOLOGIC DIAGNOSIS:  Cutaneous onchocerciasis

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL MICROSCOPIC FINDINGS:

Cutaneous lesions:

Ocular lesions (caused by microfilaria):

DIFFERENTIAL DIAGNOSIS:

For gross findings:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Cooper BJ, Valentine BA. Muscle and tendon. In: Maxie MG, ed. Jubb, Kennedy,and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. St. Louis, MO: Elsevier; 2016: 247.
  2. Gardiner CH, Poynton SL. An Atlas of Metazoan Parasites in Animal Tissues. Washington, DC: Armed Forces Institute of Pathology; 2006: 35, 38.
  3. Hestvik G, Ekman S, Lindberg R. Onchocercosis of an intervertebral joint capsule causing cervical vertebral stenotic myelopathy in a horse. J Vet Diagn Invest. 2006; 18:307-310.
  4. Jones TC. Diseases caused by parasitic helminths and arthropods. In: Jones TC, ed. Veterinary Pathology. 6th ed. Baltimore, MD: Williams and Wilkins; 1997: 642-644.
  5. Mauldin EA, Peters-Kennedy J. Integumentary system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. St. Louis, MO: Elsevier; 2016: 687-8.
  6. Radostits OM. Other skin conditions in horses and ruminants. In: Radostits OM, ed. Veterinary Medicine: A Textbook of the Diseases of Cattle, Sheep, Pigs, Goats and Horses. 9th ed.  Philadelphia, PA: W. B. Saunders Company; 2000:1375. 
  7. Rooney JR. Eyes and ears. In: Rooney JR, ed. Equine Pathology. 1st ed. Ames, IA: Iowa State University Press; 1996: 125-126,162, 294-295.
  8. Saenchez MD, Orita VM, Nolan TJ. Pathology in practice. J Am Vet Med Assoc. 2012;240(4):385-387.
  9. Scott D. Parasitic diseases.  In: Scott D ed. Large Animal Dermatology. 1st ed. Philadelphia, PA: W.B. Saunders Company; 1988: 255-259.
  10. Smith BP. Skin diseases. In: Large Animal Internal Medicine. Smith BP, ed. 2nd ed. St. Louis, MO: Mosby; 1996: 1388-1391, 1427-1428.
  11. Sreter T, Szell Z, Egyed Z, Varga I. Ocular onchocerciasis in dogs: A review. Vet Rec. 2002; 151:176-180.
  12. Wilcock BP, Njaa BL. Special senses. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. St. Louis, MO: Elsevier; 2016: 452.
  13. Zarfoss MK, Dubielzig RR, Eberhard ML, Schmidt KS. Canine ocular onchocerciasis in the United States: Two new cases and a review of the literature.  Veterinary Ophthalmology. 2005: 8:51-57.


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