BK Polyomavirus

Epidemiology and Etiology:

· Opportunistic

· Kidney transplant

· First 3 months after transplantation

· Ubiquitous

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Common sites:

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Gross features:

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Histologic features:

· Urothelial cells with hyperchromatic smudged chromatin (‘decoy’ cells

· Acute tubular interstitial nephritis

· Tubular cells with enlargement and nuclear clumping, irregularity, and hyperchromatism

· Smudged, basophilic appearance

· Collecting ducts first affected

Immunophenotype:

Marker:

Sensitivity:

Specificity:

Molecular features:

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Other features:

· Fever

· Ureteric stenosis

· Hemorrhagic cystitis

· Acute renal failure

· Premature graft failure

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References:

· Silverberg SG, DeLellis RA, Frable WJ, LiVolsi VA, Wick MR. Silverberg's Principles and Practice of Surgical Pathology and Cytopathology: 2-Volume Set. 4th ed. Churchill Livingstone; 2005.