SYSTEMIC PATHOLOGY
DIGESTIVE SYSTEM
October 2018
D-N09 (NP)

Signalment (JPC# 2547361):  6-year-old male military macaw (Ara militaris)

HISTORY:  Behavior and appetite were normal at time of death.  The macaw was exposed to a conure that died with nonspecific signs.

HISTOPATHOLOGIC DESCRIPTION:  Liver:  Effacing approximately 80% of hepatic parenchyma and separating and surrounding remaining islands of normal hepatocytes is an un-encapsulated, infiltrative, moderately cellular neoplasm composed of polygonal cells arranged in irregular, branching, and anastomosing tubules and acini on a moderate fibrovascular and desmoplastic stroma. Neoplastic cells have variably distinct cell borders, a moderate amount of pale eosinophilic and vacuolated cytoplasm, one round to oval nucleus, with finely-stippled chromatin and 1-2 distinct basophilic nucleoli. The mitotic rate is 1 per 10 HPF, and there is occasional single cell necrosis within the neoplastic cells. Multifocally, hepatocytes are swollen with vacuolated cytoplasm (glycogen degeneration) or shrunken with brightly eosinophilic cytoplasm and a pyknotic nucleus (necrosis).  There are low numbers of lymphocytes and plasma cells scattered through the hepatic parenchyma.

Mucosa, oropharynx (per contributor):  Extending from a thin fibrovascular stalk is an exophytic neoplasm composed of polygonal cells undergoing squamous differentiation arranged in anastomosing trabeculae which form papillary frond-like projections supported by a fine fibrovascular stroma.  Neoplastic cells have variably distinct cell borders, a moderate amount of eosinophilic cytoplasm, a round to oval nucleus with finely-stippled chromatin and a single prominent nucleolus.  The mitotic rate is 1 per 10 hpf.  Keratohyalin granules of the stratum granulosum are prominent and irregularly shaped.  Multifocally, there is parakeratotic hyperkeratosis and epidermal erosions.  Multifocally, there are low numbers of heterophils which transmigrate through the epidermis and low numbers of lymphocytes, plasma cells, and fewer heterophils in the dermis.

MORPHOLOGIC DIAGNOSIS:  

  1. Liver: Cholangiocarcinoma, military macaw (Ara militaris), avian.
  2. Mucosa, oropharynx (per contributor): Papilloma.

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ULTRASTRUCTURAL FINDINGS

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Cullen JM, Stalker MJ. Liver and biliary system. In: Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. St. Louis, MO: Elsevier; 2016:348-349.
  2. Gelberg HB. Alimentary system and the peritoneum, omentum, mesentery, and peritoneal cavity. In: Zachary JF ed. Pathologic Basis of Veterinary Disease. 6th St. Louis, MO: Elsevier Mosby; 2017:350, 454.
  3. Munday JS. Bovine and human papillomaviruses: A comparative review. Vet Pathol. 2014;51(6)1063-1075.
  4. Rodriguez-Barbon A, Cowen R, Knott C, Hughes K, Allinson K, Williams CV, Routh A. Neoplasia in three aye-ayes (Daubentonia madagascariensis). J Comp Path. 2018;159:16-20.


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