Cytologic features of metastatic transitional cell carcinoma.

Cytologic preparations containing metastatic transitional cell carcinoma (MTCC) from 18 sites in 16 patients were reviewed to determine characteristic morphologic features. The patient group included 13 males and 3 females with a mean age of 66 years. Primary TCC occurred in the bladder (14), kidney (1), and ureter (1); nearly all the primary tumors were poorly differentiated and most were invasive at the time of diagnosis. The cytologic specimens were derived from lymph nodes (6), liver (4), serous fluids (2), pelvic soft tissue (2), subcutaneous nodules (2), and lung (1). One patient presented with MTCC in Pap smears. Cytologically MTCC presented as loosely cohesive, moderate to markedly pleomorphic cells which occurred singly and in syncytial clusters. The malignant cells were usually large with abundant granular or fibrillar cytoplasm and the cell borders were generally distinct. Most nuclei were large and hyperchromatic with irregularly distributed granular chromatin and prominent nucleoli. The most distinctive features were the presence of spindled, pyramidal, and/or racquet-shaped malignant cells with eccentric nuclei and cytoplasmic features of both squamous and glandular differentiation including endoplasmic/ectoplasmic interfaces and intracytoplasmic vacuoles. Although clinical history is most useful in the diagnosis of MTCC, these morphologic features in cytologic preparations of malignant epithelial neoplasms may be helpful. In the absence of a known primary TCC, it is doubtful that a definite cytologic diagnosis could be made; however, the characteristic cell shapes and cytoplasmic features may be suggestive of MTCC.