JPC SYSTEMIC PATHOLOGY
Signalment (JPC 1629346): Dog
HISTORY: Slide U-M22a: Incidental histologic finding in a dog
HISTOPATHOLOGIC DESCRIPTION: Kidney: Multifocally within the cortex, proximal tubular epithelial cells contain single brightly eosinophilic, acicular, 5 by 10-15 um intranuclear inclusions which are occasionally elongate and distend the nuclei. Focally, there is distortion of the architecture a glomerular tuft by a closely packed aggregate of polygonal foam cells with vacuolated, pale eosinophilic cytoplasm (glomerular lipidosis). Multifocally, proximal tubular epithelial cells and less often glomerular podocytes contain brown to yellow globular intracytoplasmic pigment.
Liver: Occasional hepatocytes contain intranuclear inclusions as previously described.
MORPHOLOGIC DIAGNOSIS: 1. Kidney, proximal tubule epithelium: Intranuclear inclusions, multiple, with minimal glomerular lipidosis, breed not specified, canine
2. Liver, hepatocytes: Intranuclear inclusions, few
Signalment (JPC Accession #850256-4A): Rhesus monkey
HISTORY: Slide U-M22b: Incidental histologic finding in a rhesus monkey
HISTOPATHOLOGIC DESCRIPTION: Kidney: Multifocally, pelvic urothelial cells contain 1 to 2 round to oval, up to 10 um diameter, brightly eosinophilic, granular, intracytoplasmic inclusion bodies.
MORPHOLOGIC DIAGNOSIS: Kidney, pelvic urothelium: Intracytoplasmic inclusions, few, rhesus macaque, nonhuman primate
ETIOLOGIC DIAGNOSIS: Nonspecific renal and hepatic inclusions.
· Nonspecific intranuclear inclusions are a common finding in the kidneys and liver of older dogs (ACIN inclusions); although crystalline, they are non-birefringent
· In the kidneys they are in the proximal tubules and are eosinophilic, crystalline and referred to as “brick inclusions”
· Inclusions may also be found in the urinary bladder of the dog and monkey
· Not considered pathologically significant
TYPICAL CLINICAL FINDINGS: None
TYPICAL GROSS FINDINGS: None
TYPICAL LIGHT MICROSCOPIC FINDINGS:
· Variably oval or rectangular, brightly eosinophilic, crystalline, refractile and non-birefringent intranuclear or intracytoplasmic inclusions most often in the proximal tubules
· Varies with the type of inclusion but are apparently composed of protein
ADDITIONAL DIAGNOSTIC TESTS:
· EM, toxicology, or PCR to rule out infectious or toxic causes
· Inclusions are acid-fast
· Viral infections (herpesvirus, parvovirus, morbillivirus, polyomavirus, adenovirus, iridovirus) with intranuclear inclusions
· Lead toxicity: Intranuclear inclusions may be present in renal tubular epithelium; inclusions are acid-fast and noncrystalline
· Cytoplasmic invagination into the nucleus can be mistaken for viral inclusions; may be evident in hepatocytes in a chronically injured liver
· Mice: Eosinophilic neuronal intracytoplasmic inclusions have been reported in the thalamus of aging mice and in the renal tubular epithelium of ICR mice
· Goats may have large eosinophilic intranuclear inclusions in hepatocytes and renal collecting duct epithelium; the pathogenesis is unclear but it is referred to as “nuclear glyogenosis”
1. Baze WB, Steinbach TJ, Fleetwood ML, Blanchard TW, Barnhart KF, McArthur MJ. Karyomegaly and intranuclear inclusions in the renal tubules of sentinel ICR mice (mus musculus). Comp Med 2006;56(5):435-8.
2. Cianciolo RE, Mohr FC. Urinary system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. 6th ed. St. Louis, MO: Elsevier; 2016:430.
3. Cullen JM, Stalker MJ. Liver and biliary system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer's Pathology of Domestic Animals. 6th ed. Vol 2. Philadelphia, PA: Elsevier Saunders;2016:270.