Other Malignancies in Urinary Cytology
Rose Anton, MD
Nour Sneige, MD
Key Facts
Top Differential Diagnoses
Small cell carcinoma: Resembles small cell carcinoma of other sites; necrosis present; neuroendocrine markers and TTF-1 (+)
Renal cell carcinoma: May be associated with capillaries; pax-8(+)
Prostate adenocarcinoma: Monotonous bland nuclei, prominent nucleoli, acinar formation; PSA and PAP (+)
Colorectal adenocarcinoma: Round or elongated, cigar-shaped, hyperchromatic nuclei; necrosis; CDX-2 and villin (+), CK7(-) (CK20[+] in both colorectal and urothelial carcinomas)
Melanoma: Often dyshesive; melanin pigment may be absent; nuclei may show typical features of melanomas elsewhere; S100, HMB-45, and Melan-A (+)
 (A) Rounded tumor cells  intimately associated with small, elongated endothelial cells  suggest renal cell carcinoma (RCC) on this Pap stain. (B) RCC on Pap stain shows vesicular chromatin and finely vacuolated cytoplasm, but additional history and immunostains may be necessary for accurate diagnosis. (C) Pap-stained bladder washing shows prostatic adenocarcinoma. The nuclei are fairly bland, round, and monotonous. Nucleoli are prominent  . (D) The prostatic adenocarcinoma in this Pap stain shows prominent nucleoli  and a vague acinar pattern  . |
CLINICAL ISSUES
Presentation
Primary small cell carcinoma is rare (< 1% of all bladder malignancies)
May be involved by metastasis (breast, lung, melanoma) or direct extension (kidney, prostate, ovary, cervix, large bowel)
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