Rationale: The incidence of primary large-cell neuroendocrine carcinoma (LCNEC) is extremely rare in the urinary tract. In the present study, we investigated a case of primary LCNEC associated with the upper ureter.
Patient concern: A 58-year-old Korean female patient with right ureter mass, which was accidentally detected. An enhancing mass measuring 3.3 cm in size was found in the computed tomography (CT) scan. No definitive evidence of lymph node and distant metastasis was observed.
Diagnosis: Histopathological analysis revealed large atypical epithelial cells in upper ureter mass, based on neuroendocrine morphology. Immunohistochemistry was positive for synaptophysin, CD 56, and cytokeratin. Accordingly, the upper ureter mass was finally diagnosed as LCNEC stage III, pT3 cN0 cM0.
Intervention: Right nephroureterectomy was conducted.
Outcomes: Multiple metastatic lesions were detected in the right adrenal, paracaval, and right pararenal space of the patient in a CT scan 3 months post-surgery. The patient chemotherapy and radiation therapy were proceeded for metastatic and recurred mass. But patient died by multiorgan failure LESSONS:: In summary, this case study demonstrated that LCNEC can develop even in the upper ureter for the first time, despite the absence of neuroendocrine cells in the normal urothelium. The occurrence of LCNEC in the ureter is still very rare but is possible. Therefore, further studies are needed to establish appropriate treatment strategies.