Chihuahua Case

Species: Canine

Breed: Chihuahua

Age: 7 Years

Gender: Female Spayed

Source/History: Left kidney in full

Low power (1X)


High magnification (40X)


High Magnification (40X) – A vessel adjacent to the adrenal gland containing an embolus of neoplastic tissue
Click here for the IDEXX Pathology Report on this case.

Microscopic Description:

Most of the left kidney is effaced and replaced by a neoplasm comprised of large lobules of tubular structures invested by delicate fibrovascular stroma that contains a few lymphocytes and plasma cells. The neoplastic cells are cuboidal and contain amphiphilic cytoplasm. Nuclei are oval to round with a prominent large single nucleolus. Occasionally to nucleoli are present. Large areas of necrosis are present throughout the tumor. The tumor is also effacing and replacing a portion of the left adrenal gland. Tubular structures of the tumor are present within vessels surrounding the adrenal gland.

Microscopic Interpretation:

Left kidney: Renal carcinoma with necrosis, fibrosis and pleocellular inflammation

Mitotic Count: 16

Excision: Extends into connective tissue surrounding the kidney with metastasis to the adrenal gland.

Vascular invasion: Observed and Prominent


Renal carcinomas are the most common primary renal tumors of dogs, cattle, and horses. They are sporadically reported in cats, sheep, and pigs. These tumors are generally seen in older animals. The tumor has however been reported in dogs less than 2 years of age. In cats, the mean age at diagnosis is 9 years with no breed or sex predilection. Males are affected about twice as often as bitches. Paraneoplastic syndromes associated with this tumor, although rare, include extreme neutrophilic leukocytosis, disseminated intravascular coagulation, leukomoid blood response, and bone infarcts. These tumors tend to grow expansively but satellite nodules often develop from local permeation. Invasion of the renal vein is possible but may not result in metastases. Peritoneal implantation sometimes occurs. This tumor, when it does metastasize, often spreads to the lungs, liver, brain, heart, and skin. In some cases, unilateral nephrectomy is curative.

Image Notes:

  1. Low power (1X) view of the kidney (Left) and the adrenal gland (right). The kidney is effaced by tumor, there are metastatic nodules in the adrenal gland.
  2. High magnification view of the lesion (40X), demonstrating neoplastic cords and small acinar type structures effacing the normal renal parenchyma.
  3. A vessel adjacent to the adrenal gland contains an embolus of neoplastic tissue (40X).


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