Findings

Microscopic examination of the mass exhibited a large, mostly necrotic benign polypoid epithelial "polyp"/mass with prostatic-type epithelium, with a cystic growth pattern. The neoplasm, including the necrotic areas, measured 9.2 cm in its greatest dimension. The mass appeared to arise from the prostatic urothelium and into the bladder mucosa, with involvement of the right seminal vesicle area. Extensive acute and chronic inflammation of the bladder wall surrounding the necrotic areas was noted. All margins were negative. Immunohistochemical staining performed was positive for PSAP, PSA, NKX3.1, p63, CK903, and negative for GATA3, CK7, AMACR, and CK20. However, GATA3 and CK7 were positive within the urothelial lining only.

Differential diagnosis:

• Urothelial carcinoma with glandular differentiation
• Papillary urothelial neoplasm
• Benign prostatic hyperplasia (BPH)
• Nephrogenic adenoma
• Polypoid or papillary cystitis
• Prostatic-type polypoid urothelial lesions
• Cystitis cystica
• Cystitis glandularis

Diagnosis: Prostatic-type polypoid urothelial lesions