Background: Neuroendocrine tumors of the ureter are extremely rare. There are only a few case reports in the past decades. Their clinicopathologic features, therapy and prognosis are not that clear.
Methods: 5 cases of ureteral neuroendocrine tumors were collected and reviewed of the literature. Histomorphology, immunophenotype and ultrastructural features were observed by HE, immunohistochemistry, special staining and electron microscopy. The clinical pathological data were retrospectively analyzed and followed up.
Results: Among the 5 patients, 1 was female and 4 were male, aged 62-82 years. 2 cases manifested intermittent hematuria, 1 had lower abdominal pain with frequent urination and dysuria, 1 with hydronephrosis, and 1 had no manifestations. All the 5 patients were treated with nephroureterectomy, 3 of which were also treated with excision of bladder cuff, 1 also had lymphadenectomy. On presentation, 2 cases in T2N0M0 (stage II), 2 cases in T3N0M0 (stage III), and 1case in T3N2M0 (stage IV). 2 cases were small cell neuroendocrine carcinoma, 1 was large cell neuroendocrine carcinoma and 2 were atypical carcinoid. The tumor cells were positive for neuroendocrine markers (CD56, CgA, Syn). 1 case of vimentin-positive small cell neuroendocrine carcinoma has a very good prognosis. Grimelius stain and electron microscopy observation showed numerous neuroendocrine granules in the cytoplasm.
Conclusion: Ureteral neuroendocrine tumors are extremely rare. Neuroendocrine markers (CD56, CgA, Syn) and epithelial markers (CKpan, CK7) are usually helpful. Grimelius special staining and electron microscopy observation can help to make a final diagnosis. Radical surgery together with postoperative adjuvant chemotherapy can improve the survival of patients. Vimentin may play a role in predicting the prognosis.
Keywords: Grimelius stain; Immunohistochemistry; Neuroendocrine tumors; Prognosis; Ultrastructural observation; Ureter.
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