Renal neuroendocrine tumors

Abstract

Objectives:Neuroendocrine tumors (NETs) are uncommon tumors that exhibit a wide range of neuroendocrine differentiation and biological behavior. Primary NETs of the kidney, including carcinoid tumor, small cell carcinoma (SCC), and large cell neuroendocrine carcinoma (LCNEC) are exceedingly rare.Materials and Methods:The clinicopathologic features of renal NETs diagnosed at a single institution were reviewed along with all reported cases in the worldwide literature.Results:Eighty renal NETs have been described, including nine from our institution. Differentiation between renal NETs and the more common renal neoplasms (renal cell carcinoma, transitional cell carcinoma) can be difficult since clinical, radiographic, and histopathologic features overlap. Immunohistochemical staining for neuroendocrine markers, such as synaptophysin and chromogranin, can be particularly helpful in this regard. Renal carcinoids are typically slow-growing, may secrete hormones, and pursue a variable clinical course. In contrast, SCC and LCNEC often present with locally advanced or metastatic disease and carry a poor prognosis. Nephrectomy can be curative for clinically localized NETs, but multimodality treatment is indicated for advanced disease.Conclusions:A spectrum of NETs can rarely occur in the kidney. Renal carcinoids have a variable clinical course; SCC and LCNEC are associated with poor clinical outcomes. Diagnosis of NETs, especially LCNEC, requires awareness of their rare occurrence and prudent use of immunohistochemical neuroendocrine markers.

Primary large-cell neuroendocrine carcinoma of the scrotum

“…Histopathologic examination classifi ed the tumor as largecell neuroendocrine carcinoma. Poorly diff erentiated NETs, which carry a poor prognosis, rarely secrete hormone substances and often present with local metastases [8]. NETs in the gastrointestinal tract and lungs are more common and have a more detailed classifi cation; rare NETs in the genitourinary tract are classifi ed into two types: well diff erentiated and poorly diff erentiated.…”

Review of small cell carcinoma of the kidney with focus on clinical and pathobiological aspects

“…The size of tumor cells in LCNEC is larger than that of SmCC. Abundant cytoplasm, vesicular chromatin, prominent nucleoli and perilobular palisading are seen [2][3][4]18]. High grade urothelial carcinoma including the plasmacytoid variant or lymphoepithelioma-like variant should be distinguished from SmCC [23].…”

“…The cut surface of the tumor shows white, gray-white or gray-yellow color [10,16,17]. Multilobulation is frequently seen [18]. Invasion into the inferior vena cava or renal vein and metastasis to lymph nodes are frequent [3,6,7,10,11,15].…”

“…Tumor thrombectomy may be effective [10]. Radiation therapy can be used for postoperative residual local disease or metastatic lesions [18,20].…”

“…to rule out other more common renal neoplasms within the spectrum of malignant small round blue cell tumors [10]. However, as renal SmCC often shows extra-renal extension, the tumor may be amendable to com- plete resection [18]. Regarding chemotherapy, platinum-based chemotherapy improves overall survival [7].…”