JPC SYSTEMIC PATHOLOGY

RESPIRATORY SYSTEM

September 2017

P-N03

 

Signalment (AFIP # 1946538):  Thirteen‑year‑old, female, thoroughbred horse

HISTORY:  Unknown

HISTOPATHOLOGIC DESCRIPTION:  Lung:  Affecting approximately 50% of the section, centered on and effacing a large bronchus, and compressing adjacent pulmonary tissue is an encapsulated, well-circumscribed, highly cellular neoplasm composed of round to polygonal cells arranged in loose nests, rows and sheets on a fine, fibrovascular stroma.  Neoplastic cells exhibit mild anisocytosis and anisokaryosis, have abundant cytoplasmic eosinophilic granules, an eccentric, round, nucleus with finely stippled chromatin and often one nucleolus.  0-1 mitotic figures per 10 40x HPFs are observed.  Multifocal areas of hemorrhage are present within the parenchyma adjacent the neoplasm; these areas are admixed with moderate numbers of hemosiderin-laden macrophages (siderophages).  Epithelial cells within entrapped and adjacent bronchi and bronchioles are hyperplastic, piling up to 4 layers thick, while lumina are often expanded by variable amounts of mucin, which also fills adjacent alveoli.

MORPHOLOGIC DIAGNOSIS:  Lung:  Granular cell tumor, thoroughbred, equine

GENERAL DISCUSSION: 

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS: 

ULTRASTRUCTURAL FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS: 

COMPARATIVE PATHOLOGY: 

References: 

  1. 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 Limited; 2016:498.
  2. Lopez A, Martinson SA. Respiratory system, mediastinum and pleurae. In: Zachary JF ed. Pathologic Basis of Veterinary Disease, 6th St. Louis, MO: Elsevier; 2017:554.
  3. Weber K, Garman RH, Germann PG, Hardisty JF, Krinke G, Millar P, Pardo ID. Classification of neural tumors in laboratory rodents, emphasizing the rat. Toxicol Pathol. 2011 Jan; 39(1):129-51.
  4. Fox, JG, Muthupalani S, Kiupel M, Williams B. In:  Fox JG, Marini RP, eds.  Biology and Diseases of the Ferret, 3rd  2014: 617. 


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