Fine needle aspiration cytology of metastatic urothelial carcinoma: Study of seven cases with review of literature

BACKGROUND: Metastatic urothelial carcinoma (UC) is rarely described in cytology literature. Appropriate cytological diagnosis is important in certain clinical scenarios to exclude a second primary. AIMS: To delineate cytological features that are helpful in diagnosing metastatic UC. MATERIALS AND METHODS: The study included seven male patients with age range of 48 – 72 years. These patients were diagnosed cases of UC and had now presented with lesions in liver, lungs, bones or lymph nodes. Computed tomographic (CT)/ultrasonographic (USG) guided fine needle aspiration cytology (FNAC) was available from one of these sites. RESULTS: Cercariform cells (CCs) could be identified in five out of seven cases. In four cases, multilayered papillary fragments (MPFs) were identified which were reminiscent of histopathologic appearance of UC. One of these two morphologic features was present in all the cases. However, both CC cells and MPFs were present only in two cases. CONCLUSION: Previous clinical history is indispensible while diagnosing metastatic UC. MPFs and CC cells are strong morphologic clues to urothelial origin. In poorly differentiated tumors, differentiation from other epithelial tumors may not be possible on the basis of morphology alone.