Primary Small-Cell Neuroendocrine Carcinoma of the Kidney with Urothelial Carcinoma: A Case Series and Literature Review

Abstract

Primary small-cell neuroendocrine carcinoma of the kidney with urothelial carcinoma is very rare, and it has a unique pathomorphology and immunohistochemical phenotype. Since it is easily missed diagnosed or misdiagnosed, it needs to be differentiated from a variety of other tumors. In addition to poor prognosis, the carcinoma also has strong invasive ability. The clinicopathological characteristics, immunohistochemical phenotype, and diagnosis and differential diagnosis of four patients with primary smallcell neuroendocrine carcinoma with urothelial carcinoma were retrospectively analyzed, and the relevant literature was reviewed. Three cases occurred in the left kidney and one case occurred in the right kidney. The main clinical symptoms were gross hematuria and waist pain. Tumor histological morphology and immunohistochemical markers support small-cell neuroendocrine carcinoma with urothelial carcinoma.