February 2019

SIGNALMENT (JPC #2064150):  A dog; age, sex and breed unknown 

HISTORY:  This dog had clinical signs of hyperadrenocorticism.

HISTOPATHOLOGIC DESCRIPTION:  Adrenal gland: Infiltrating, effacing and replacing normal adrenal gland architecture and compressing the pre-existing adrenal cortex is a non-encapsulated, poorly demarcated, multilobular, densely cellular neoplasm composed of polygonal cells arranged in cords, nests, and packets on a fine fibrovascular stroma forming lobules separated by dense reticulations of collagen. Neoplastic cells have indistinct borders, a moderate amount of microvacuolated eosinophilic cytoplasm, round to oval nuclei with finely stippled chromatin and one magenta nucleolus. There is mild to moderate anisocytosis and anisokaryosis and the  mitotic count is upwards of 3 per individual 400x powered objective. Multifocally, neoplastic cells and cells within the remaining adrenal cortex contain large clear vacuoles with hyperchromatic to pyknotic nuclei (lipoidal degeneration).  Multifocally scattered throughout the neoplasm are single cell to larger areas of necrosis, hemorrhage, and mineral deposition.

MORPHOLOGIC DIAGNOSIS:  Adrenal gland: Adrenocortical carcinoma, breed unspecified, canine.








Adrenal dependant

Pituitary dependant

Tests to confirm hyperadrenocorticism regardless of cause include:

Resting cortisol

Normal to Elevated

Normal to Elevated

ACTH stimulation

Normal to exaggerated (up to 50% normal)

Normal to exaggerated

Low dose dex suppression

Will not suppress

Will not suppress

Urine cortisol:creatinine (best to rule OUT cushings)

Increased (may also increase with stress)

Increased (may also increase with stress)

Tests to distinguish the cause:

Low dose dex suppression at 4 and 8 hours

No suppression (escape) at 4 hours

Most (75-98%) escape by 8 hours (so if suppressed at 4hrs and escape by 8 hrs= PDH)

High dose dex suppression

No suppression

75% suppress

Endogenous ACTH


Normal to high

Corticotrophin releasing hormone test

No response in either cortisol or ACTH

Increase in cortisol and ACTH




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  8. Miller CL, Marini RP, Fox JG. Diseases of the endocrine system. In: Fox JG, Marini RP, eds. Biology and Diseases of the Ferret. 3rd Ames, IA: John Wiley & Sons, Inc.; 2014:377-384.
  9. Miller MA. Endocrine system. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:706-708.
  10. Rosol TJ, Grone A. Endocrine glands. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. Philadelphia, PA: Saunders Elsevier; 2016:337-348.
  11. Rosol TJ, Meuten DJ. Tumors of the endocrine glands. In: Meuten DJ, ed. Tumors in Domestic Animals. 5th ed. Ames, IA: John Wiley & Sons, Inc.; 2017:782-787.

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Click on image for diagnostic series.

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