April 1997

Case of the Month

Submited by:
Mariano Alvira, Laboratory Department, Middletown Regional Hospital, Middletown, Ohio

Clinical History and Light Microscopy

A 63 year old male presented with gross hematuria. Cystoscopy revealed several large bladder "tumors". Sixteen grams of tumor were resected. Hematoxylin and Eosin (H&E)stained sections showed carcinoma with "signet ring" cell changes in many cells (Figs. 1 and 2). The preliminary impression was that of either a primary or metastatic adenocarcinoma with "signet ring" cells. Cytokeratin stains were strongly positive. (Fig. 3), but a mucicarmine stain was negative (Fig. 4). Formalin-fixed tissue was processed for electron microscopy. Consultation with a urologic pathologist was obtained as part of the quality assurance process in our institution. The consultant's opinion was:

"very high grade adenocarcinoma primary in the urinary bladder. A component of this tumor seems to be poorly differentiated transitional cell carcinoma, but in other areas, the tumor takes a signet ring cell appearance, therefore, I would characterize this as a high grade urothelial carcinoma with mixed transitional cell and signet cell differentiation."

A subsequent cystectomy showed residual carcinoma with minimal, focal invasion of the submucosa and no evidence of muscle invasion.

Figure 1. Loosely organized groups of tumor cells, some of which have a "clear" cytoplasm. H&E.	Figure 2. At higher magnification, a variably sized intracytoplasmic "clear" zone displaces the nucleus producing signet-ring cells. H&E.
Figure 3. Tumor cells, including signet-ring cells, strongly positive for cytokeratins.	Figure 4. Negative mucicarmine staining of tumor cells..

Electron Microscopy - Page 2

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