Fine-needle aspiration diagnosis of metastatic urothelial carcinoma: a review.

Urothelial carcinoma (UC) is the most common malignant neoplasm of the urinary tract. Metastases of UC are most common in the regional lymph nodes, lungs, liver, bone, and adrenal glands. Fine-needle aspiration cytology diagnosis of such metastases can be difficult, particularly in the setting of incomplete clinical history or when multiple primary neoplasms may be present. This review focuses on the cytologic features helpful in differentiating UC from its potential mimics, as well as ancillary studies that may be helpful in the distinction.