An Unusual Variant of Bladder Carcinoma: Microcystic Urothelial Carcinoma

Abstract

Microcystic urothelial carcinoma of the urinary system is an unusual type of transitional cell carcinoma. We presented a 52-year-old man with microcystic urothelial carcinoma in the bladder without significant medical history. Transurethral resection was performed and subsequent pathologic evaluation defined the lesion as a microcystic urothelial car-cinoma. Microscopic examination showed muscle invasive transitional cell carcinoma with prominent cystic features. The cysts lined by multiple layers of flattened or cuboidal cells with atypia were of varying sizes. Immunohistochemical analysis using the streptavidin-biotin peroxidase technique and immunoreactivity for different cytokeratins was performed, confirming the pathologic diagnosis. The patient underwent radical cystectomy and pelvic lymphadenectomy. The patient had no metastasis at 10-months follow-up. Microcystic urothelial carcinoma of the bladder which contains predominant irregular cystic areas can mimic benign lesions. Due to the similarity of this tumor to other cystic lesions, the pathologist should be aware of this rare entity in differential diagnosis.