Table 1. Differential diagnosis.

Pax-8: paired box gene 8; UTI: urinary tract infection; TURBT: transurethral resection of bladder tumor; CK: cytokeratin; PSA: prostatic-specific antigen; CEA: carcinoembryogenic antigen; CA125: cancer antigen 125; CD10: cluster of differentiation 10; MUC: mucin; PRap: Poly (ADP-ribose) polymerase 

	Nephrogenic Adenoma	Clear cell carcinoma	Microcystic variant urothelial carcinoma	Skene's gland cyst
Symptoms	Palpable mass, recurrent UTIs, obstructive urinary symptoms, hematuria	Hematuria, dysuria, obstructive urinary symptoms, recurrent UTIs	Hematuria, obstructive urinary symptoms	Asymptomatic, incidental finding
Size	Bimodal: 1-2 cm or 4-7 cm	4cm-6cm	1 cm-6 cm, depending on stage	<1cm
Gross appearance	Papillary lesion without invasion	Solid lesion with invasion	Sessile mass with invasion	No mass present unless in vagina
Clear cells	Only in focal solid areas	Widespread	Common	Rare
Nuclear atypia	Rare	Common	Common	Rare
Mitotic figures	Uncommon	Common	Few	Rare
Histological features	Tubules surrounded by hyalinized basement membrane	Tubulocystic pattern with hobnail and clear cells	Round-oval cystic change within nests of urothelial carcinoma	Glandular and squamous elements in ectocervical stroma
Treatment	Surgical removal	TURBT, cystectomy, chemotherapy	Surgical removal	No treatment necessary
Immunohistochemistry	PAX8, CK903, S100A1, BerEP4, Negative P63, PSA, CEA	Positive CK, CK7, CK20, CA125, CEA; Negative CD10	Positive CK7, CK20, MUC1, MUC5AC, p63, and GATA3	Positive PSA, PRaP