Clinical and Pathological Features of Primary Renal Well-Differentiated Neuroendocrine Tumor

Abstract

Primary carcinoid tumor of the kidney is an extremely rare well-differentiated neuroendocrine tumor, which is generally a low-grade malignant cancer with a good prognosis. Carcinoid tumors are rarely found in the urinary system. Here, we report a 34-year-old woman with primary renal well-differentiated neuroendocrine tumor who underwent nephron sparing surgery and no evidence of recurrence or distant metastasis was found during routine follow-up. We searched the case of renal carcinoid with the search phrase “carcinoid [title] and kidney [title]” and “carcinoid [title] and renal [title]” using the PubMed and restricted the search to articles published in English since 2013. The clinical manifestations, age, sex, tumor size, location, gross pathology, light microscopy and immunohistochemistry were analyzed. A total of 28 cases of renal carcinoid were retrieved from PubMed. Higher proportion of positive labeling of CgA, Syn, NSE and CD56 are most valuable in the diagnosis of primary renal well-differentiated neuroendocrine tumor. At present, radical nephrectomy remains the gold standard in the curative-intent therapy for well-differentiated neuroendocrine carcinoma of kidney, in metastatic renal carcinoid, long-term use of octreotide may be an effective adjuvant therapy.

Well‑differentiated neuroendocrine tumor of the right kidney: A case report

“…Certain seemingly primary renal carcinoids can constitute a metastatic focus from an undiscovered primary lesion (8)(9)(10)(11). Previous studies support a hypothesis, also known as the co-existence hypothesis, which proposes that the proliferation of scattered neuroendocrine cells originates from the epithelium of a horseshoe or polycystic kidney (12,13). It has been found that the risk of developing carcinoids in the horseshoe kidney is 62-to 82-fold higher than that noted in the normal kidney.…”

Rare renal well-differentiated neuroendocrine tumors: clinical and imaging characteristics in a series of three cases

“…Cytologically, the tumor cells exhibit fine granular “salt-and-pepper” chromatin patterns. Immunohistochemical markers such as CgA, Syn, neuron-specific enolase (NSE), and CD56 are valuable for diagnosing PRNTs ( 15 ). Surgical resection is the primary treatment for PRNTs, and several prognostic factors associated with a poor prognosis have been identified, including age at diagnosis greater than 40 years, severe initial symptoms, tumor diameter greater than 4 cm, tumor extension through the renal capsule, and presence of metastasis at the initial diagnosis ( 16 ).…”

Primary Well-Differentiated Neuroendocrine Tumor of the Kidney

“…According to a study by Krishnan et al, individuals with horseshoe kidney have around 62 times higher risk of developing NETs (5). Though the pathogenesis of carcinoid tumors of kidney has been debatable, el-Naggar et al found a loss of heterozygosity at one locus on chromosome 3p21 and hypothesized that this aberration, which is common in renal cell carcinoma (RCC), is a precursory event shared by all renal neoplasms, including carcinoid tumors (6). The most widely used functional imaging technique for cancer detection is fluorodeoxyglucose-PET (FDG-PET).…”