Cytologic Findings of Primary Small Cell Carcinoma of the Urinary Bladder: A case report / 대한세포병리학회지

ABSTRACT

Primary small cell carcinoma of the urinary bladder is a rare malignant tumor. A more rapidly fatal course may be seen in advanced stages of small cell carcinoma as compared to similar stages of urothelial carcinoma. It is very important to recognize this distinct form of bladder cancer by urinary cytology. The differential diagnosis of small cell carcinoma of the urinary bladder includes metastatic small cell carcinoma, urothelial carcinoma, and primary or secondary malignant lymphoma. This article highlights the urinary cytologic diagnosis of a case of primary small cell carcinoma. A 59-year-old male presented with gross hematuria for five months. Urinary cytology showed high cellularity consisting of tiny monotonous tumor cells in the necrotic background. The tumor cells occurred predominantly singly, but a few in clusters. The cytoplasm was so scanty that only a very narrow rim of it was seen. The nuclei were oval or round and had finely stippled chromatin. Rarely, the nuclei contain visible nucleoli. Frequently cell molding was noted in clusters. Many single cells demonstrated nuclear pyknosis or karyorrhexis. The histologic findings of transurethral resection and partial cystectomy specimen were those of small cell carcinoma. Cytologic distinction may be very difficult but careful attention to clinical features and cellualr details can classify these neoplasms correctly.