Transthoracic fine-needle aspiration cytology of non-invasive, low-grade urothelial carcinoma with lung metastasis: A case report with review of the literature

Radiological analyses in a 61-year-old patient being followed since 2005 for low-grade, non-invasive urothelial carcinoma (UC) (Ta) revealed a 5-cm pleural-based mass in the lower lobe of the right lung for which a subsequent transthoracic fine-needle aspiration cytology was performed. Upon observing the carcinoma cells consistent with UC metastasis, systemic chemotherapy was commenced. The patient underwent a metastatectomy based on the thoracic computerized tomography scan performed on the 4(th) month of treatment, which revealed notable regression. The resected tumor was morphologically similar to cells seen in the transthoracic fine-needle aspiration and was immunohistochemically positive for p63, uroplakin, thrombomodulin, CK7 and CK20 at varying degrees but was negative for TTF-1. We report a case of metastatic UC of the lung in a patient who had had a low-grade superficial UC of the urinary bladder and we discuss the cytopathological features of this rare entity in light of the literature.