Papillary urothelial hyperplasia

Papillary urothelial hyperplasia is a benign lesion of the urothelium that is associated with the subsequent development of low-grade papillary urothelial carcinoma.

General

• Benign.
• Strong association with papillary neoplasms.
  • On follow-up, in one study, >1/3 have a neoplasm; thus, follow-up is recommended.

Microscopic

Features:

• Inflammation.
• Rare papillae
  • Do not have a well-developed fibrovascular core.
• No urothelial cell atypia.

DDx:

• Low-grade papillary urothelial carcinoma.
• PUNLMP.
• Urothelial papilloma.

Image

• Papillary hyperplasia (jhu.edu).

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URINARY BLADDER, BIOPSY:
- REACTIVE PAPILLARY HYPERPLASIA, SEE COMMENT.
- NO MUSCULARIS PROPRIA IDENTIFIED.
- CYSTITIS CYSTICA ET GLANDULARIS.
- NO EVIDENCE OF MALIGNANCY.

COMMENT:
The urothelial forms rare papillary structures; these are interpreted as reactive.

The urothelium stains as follow:
CK7: positive (patchy).
CK20: very rare superficial cells (normal).
Ki-67: rare, focally increased, negative in papillary structures (<10%).
p53: negative (weak focal <20%), very rare weak in rare papillary structures (<5%).

Follow-up is recommended.

See also

• Urothelium.