Micropapillary Carcinoma of the Urinary Tract: A Cytologic Study of Urine and Fine-Needle Aspirate Samples

Abstract

Objective: Micropapillary carcinoma (MPC) is an aggressive variant of urothelial carcinoma that needs early and specific recognition. In order to determine whether this tumor variant can be recognized with cytology, we evaluated a large cytohistological series. Study Design: It was a retrospective cytohistological correlation study including 20 patients with MPC. Only those cases in which the tumor exhibited >50% of micropapillary growth were selected. Twenty exfoliative urine specimens and four needle aspirates from lymph node metastases were reviewed. Results: On histology, 14 cases were infiltrative, while 6 were exclusively superficial. Cytology was characterized by numerous small, cohesive groups and single neoplastic cells. Pseudopapillae were present in 17 cases and in 9 they were a relevant finding. Morules were present in 15 cases. Isolated microacini were seen in 14 cases. Infiltrative tumors showed more neoplastic groups. Cellular atypia was prominent in 17 cases. In 15 cases, a cytologic diagnosis of urothelial carcinoma was made. One case was diagnosed as adenocarcinoma. The remaining 4 cases were considered suspicious of malignancy. Conclusions: The peculiar morphology of MPC of the urinary tract is partially reflected on cytology, allowing in some cases a specific recognition. This is important since the aggressive behavior of this neoplasm needs rapid management and treatment.