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14 January 2015 - Case of the Week #339

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Case of the Week #339

Clinical History:
A 69 year old man with hypothyroidism had cystoscopy and a bladder biopsy for a one month history of gross hematuria.

Micro images:

Various images

What is your diagnosis?

Osteoclast rich undifferentiated carcinoma of the bladder with associated carcinoma in situ


Immunostains were obtained:









Osteoclast rich undifferentiated carcinoma of the bladder is a rare variant of high grade urothelial carcinoma (Cytojournal 2010 Sep 17;7:18) composed of a mixture of undifferentiated mononuclear carcinoma cells and osteoclast-like reactive giant cells (Mod Pathol 2006;19:161). It typically affects men age 60's to 80's, who present with gross hematuria and occasionally flank pain, renal colic or dysuria.

The distinctive histology is a mixture of multinucleated osteoclast-like reactive giant cells, highlighted above by negative staining with smooth muscle actin and S100, and mononuclear malignant epithelial cells. The giant cells are morphologically and immunohistochemically identical to osteoclasts, and are regarded as having histiocytic origin. They are cytologically bland and may be phagocytic, but lack mitotic activity. They are generally evenly distributed among the mononuclear cells, but may condense around hemorrhagic foci. The mononuclear cells have abundant cytoplasm, round to oval vesicular nuclei, mild atypia and variable mitotic activity. Typically, there is also high grade papillary urothelial carcinoma or high grade carcinoma in situ (as in this case, last H&E image).

The differential diagnosis includes bladder tumors / lesions (giant cell carcinoma, sarcomatoid carcinoma, foreign body/granulomatous reaction, urothelial carcinoma-trophoblastic variant), prostatic carcinoma / lesions (pleomorphic giant cell carcinoma, sarcomatoid carcinoma, treatment effect) and giant cell tumor of bone.

These tumors have very aggressive behavior and poor prognosis, including extensive metastasis and short survival.

Nat Pernick, M.D., President
and Shivani Thakore, Associate Medical Editor
PathologyOutlines.com, Inc.
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