Microscopic Description:

Characteristic bizarre pleomorphic multinucleated osteoclast-like giant cells.

Giant mononuclear pleomorphic cells with abundant cytoplasm.

Overall discohesive growth pattern.

Desmoplastic stroma and cells proliferating in a “single-cell” pattern.

Often coexists with a concurrent conventional high-grade urothelial carcinoma.

This clue may assist in differentiating the origin between prostate and urothelial carcinoma.

Immunohistochemistry (IHC): Urothelial component is immunopositive for CKs, EMA, GATA-3, p63, thrombomodulin, or uroplakin III.

Osteoclast-type giant cells are CD68 positive and negative for βHCG (trophoblastic giant cells).

In case of poorly differentiated urothelial component a panel of Immunostains including melanoma, lymphoid, trophoblastic and epithelial markers, and antibodies against thrombomodulin, uroplakin, and PSA should be performed.

Discussion:

Age range: 55 to 88 years

Male predominance

Clinical features: hematuria, dysuria and frequency

Urothelial neoplasms of the urinary bladder are classified into two main categories:

  1. Papillary
  2. Non-papillary

Bladder carcinomas show high tendency for divergent differentiation

Pleomorphic giant cell carcinoma is a rare and aggressive variant of urothelial carcinoma

Histologically resembles giant cell carcinoma of ‘lung’ and can present significant diagnostic challenges

References:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8302384/

https://www.pathologyoutlines.com/topic/bladderundifferentiatedosteoclast.html

https://pubmed.ncbi.nlm.nih.gov/19467692/

https://www.nature.com/articles/modpathol200926

CASE IMAGES