JPC SYSTEMIC PATHOLOGY
Cardiovascular system
April 2019
C-P03

SIGNALMENT (JPC #1844710):  A breed unspecified dog

HISTORY:  None

MICROSCOPIC DESCRIPTION:  Lung:  Focally, a pulmonary artery is moderately dilated and tortuous.  The internal elastic lamina is segmentally effaced and the tunica intima is thickened up to 20x by plump, reactive fibroblasts and a moderate amount of fibrous connective tissue and fewer smooth muscle cells that forms frond-like proliferations into the lumen, which are often lined by hypertrophied (reactive) endothelial cells (proliferative arteritis) and infiltrated by few lymphocytes, plasma cells, eosinophils and neutrophils.  Peripherally, in the tunica intima, there are few small blood vessels lined by reactive endothelial cells arranged perpendicularly to the fibroblasts and connective tissue (granulation tissue).  Within the arterial lumen, there are multiple cross sections of adult male and female filarid nematodes up to 1 mm in diameter with a thin eosinophilic cuticle, prominent lateral chords that have an internal lateral cuticular ridge, tall coelomyarian and polymyarian musculature, a small intestine lined by few multinucleate epithelial cells and paired uteri or a single gonad.  Multifocally, arteriole lumina are narrowed or partially occluded by a fibroblastic myoinitimal proliferation similar to the pulmonary artery, and are surrounded by numerous macrophages, eosinophils, lymphocytes and plasma cells.  Diffusely, alveolar septa are moderately thickened by an increased number of alveolar macrophages, fewer plasma cells, lymphocytes and eosinophils.  Within the bronchial and bronchiolar lumina and peribronchilar connective tissue, there are numerous eosinophils, neutrophils, lymphocytes, fibrin, edema and hemorrhage. 

MORPHOLOGIC DIAGNOSIS:

  1. Lung, artery: Endarteritis, proliferative and villous, chronic, focally extensive, moderate, with intra-arterial male and female filarid nematodes, etiology consistent with Dirofilaria immitis, breed unspecified, canine.
  2. Lung: Pneumonia, eosinophilic, histiocytic, and lymphoplasmacytic, multifocal, moderate, with multiple granulomas.

ETIOLOGY:  Dirofilaria immitis

ETIOLOGIC DIAGNOSIS:  Pulmonary dirofilariasis

GENERAL DISCUSSION:

PATHOGENESIS:

LIFE CYCLE:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

Special histochemical stains such as Movat or Verhoeff-van Gieson will aid in identifying the internal elastic lamina and determining the degree of myointimal proliferation

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Bourque AC, Conboy G, Miller LM, Whitney H. Pathological findings in dogs naturally infected with Angiostrongylus vasorum in Newfoundland and Labrador, Canada. J Vet Diagn Invest. 2008;20(1):11-20.
  2. Caswell JL, Williams KJ. Respiratory system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. St. Louis, MO: Elsevier; 2016:492, 513.
  3. Gardiner CH, Poynton SL. An Atlas of Metazoan Parasites in Animal Tissues. Washington, DC: Armed Forces Institute of Pathology; 1999:5-6; 35-39.
  4. Miller LM, Gal A. Cardiovascular system and lymphatic vessels. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:568-569, 615-616.
  5. Robinson WF, Robinson NA. Cardiovascular system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. St. Louis, MO: Elsevier; 2016:83-85.


Click the slide to view.



Click on image for diagnostic series.



Back | Home | Contact Us | Links | Help |