Renal Neuroendocrine Tumor: A Case Report with Evaluation of Grading Criteria and Relationship with Carbonic Anhydrase 9 Immunoreactivity.

Neuroendocrine tumors (NETs) are only exceptionally primary to the kidney. At present, scant information is known regarding the behavior and prognosis of renal NETs, especially according to the assessment of grading parameters used for NETs originating from other more commonplace sites such as the pancreas and lungs. There are only rare reports of grade assessment in renal NETs, with most of these reports relying upon now antiquated World Health Organization gastroenteropancreatic and lung/thymus criteria. As an additional prognostic factor, positive CA9 staining in NETs may correlate with elevated grade, stage and risk of metastasis while serving as a potential target of chemotherapy and immunotherapy and indicator of Von Hippel-Lindau Syndrome. Rarer still are descriptions of renal NETs presenting with renal cell carcinoma in the ipsilateral or contralateral kidney. Thus, we present a patient with a primary renal NET of the right kidney with regional lymphovascular invasion and distant metastasis with an emphasis on grading criteria concordant with the World Health Organization 2022 gastroenteropancreatic and lung/thymus systems. In addition, we discuss unusual staining for CA9 in the patient's tumor and a concomitant left kidney clear cell renal cell carcinoma that may act as a clinicopathologic mimic of Von Hippel-Lindau Syndrome.

Well­differentiated neuroendocrine tumor of the right kidney: A case report.

Neuroendocrine tumors (NETs) are tumors originating from neuroendocrine cells and peptidergic neurons. Primary renal well-differentiated NETs (WDNETs) are rare and only sporadic cases have been reported worldwide. In November 2021, a 45-year-old female patient was admitted to The Affiliated Hospital of Zunyi Medical University (Zunyi, China) with right-sided lumbago. Abdominal computed tomography revealed a 44×34×70-mm mass in the right kidney. Following a complete examination, a laparoscopic partial nephrectomy of the right kidney was performed under general anesthesia. The postoperative pathology indicated a well-differentiated NET of the right kidney. There was no tumor recurrence or metastasis during the 1-year follow-up period. WDNETs are rare, their clinical and imaging findings are not specific, and their diagnosis depends on immunohistochemical analysis. The degree of malignancy is low and the prognosis is positive. Surgical resection is often the first choice, and long-term follow-up is required.

Primary Renal Well-Differentiated Neuroendocrine Tumors: Analyis of Six Cases from a Tertiary Care Center in North India with Review of Literature.

Well-differentiated renal neuroendocrine tumors are rare tumors. As their biologic behavior is not fully known, there is a need to know more about these cases. We performed a retrospective chart review of all the cases diagnosed with renal neuroendocrine tumors from January 2016 to December 2020 (five years) in order to understand their clinical features, morphological characteristics and outcome. We included six cases with mean age of 46.2 years (4 males) in our study. All patients underwent radical nephrectomy. Histologically all showed tumor disposed in nests and trabeculae and majority of the tumors belonged to well-differentiated neuroendocrine tumor Grade 1 (WHO criteria of gastoroenteropancreatic neuroendocrine neoplasms). Lymph node metastasis was seen in two cases at the time of clinical presentation. All the tumors were diffusely positive for neuroendocrine tumor markers (synaptophysin, chromogranin, NSE, CD56). Follow-up data was available in all cases with an average follow-up of two years and neither has shown evidence of metastasis or relapse till last follow-up. Role of morphological patterns and immunohistochemical markers is highlighted with the importance of including Ki-67 index in grading them to better understand their outcome.

Solitary late metastasis of primary renal cell carcinoid tumor to the extraocular muscles imaged with indium-111 octreotide.

A 75-year-old male presented with right eye pain and proptosis. His history was significant for renal cell carcinoma treated with left nephrectomy 2 years previously. Computed tomography (CT) imaging demonstrated a 1.6-cm enhancing lesion in the right retrobulbar space. Surgical biopsy revealed a low-grade metastatic carcinoid tumor. At retrospective review, the primary renal lesion from 2 years prior was rediagnosed as consistent with a renal carcinoid tumor. Indium-111 octreotide single photon emission CT/CT imaging demonstrated a solitary metastasis within the right extraocular muscles. The patient subsequently developed additional metastases within the remaining right kidney and lung.

Primary Renal Carcinoid: Two Rare Cases at a Single Center.

Renal carcinoid tumors are exceedingly rare. These neuroendocrine masses are most frequently found in the gastrointestinal and respiratory tracts. A renal carcinoid tumor has only been documented in around 100 cases. In this article, we report two additional cases in female patients ages 53 and 63. Both tumors were found incidentally on computed tomography scans. Both women underwent radical nephrectomies. Neither has shown evidence of metastasis nor relapse to date; however, the 63-year-old woman was lost to follow-up. In conclusion, upon discovery of the asymptomatic renal mass, renal carcinoid should be a consideration in the differentiation, and if suspected, may be treated with radical nephrectomy as was done in our hospital.

An infertile female delivered a baby after removal of primary renal carcinoid tumor.

Primary renal carcinoid tumors are exceedingly rare. We report a 37-year-old woman with primary infertility, who was found to have a primary renal carcinoid tumor. She became pregnant and gave birth to a baby after removal of the tumor. This is the first case in the English literature of primary renal carcinoid tumor related with primary infertility.

Renal Neuroendocrine Neoplasms: A Single-center Experience.

BACKGROUND: Primary neuroendocrine neoplasms (NENs) of the kidney are exceedingly rare malignancies and the available literature is very limited. The natural history and response to treatments is not well characterized. We aimed to describe the presenting features, demographics, tumor characteristics, and treatment outcomes of patients with renal NENs. PATIENTS AND METHODS: We performed a retrospective analysis of all Mayo Clinic patient records with a tissue diagnosis of a primary renal NEN. Baseline patient and surgical pathologic features and treatment modalities were collected. Time to recurrence after resection and overall survival (OS) were estimated using with survival analysis. Surveillance, Epidemiology, and End Results data were used to estimate the population-wide incidence and OS. RESULTS: A total of 17 patients were included in the present study, with a median follow-up of 62.8 months. Distant metastasis was present in 29% at diagnosis, with 76% experiencing distant metastasis at any point; 24% had a horseshoe kidney. Of the 17 patients, 14 had undergone surgical resection with no evidence of disease postoperatively. Ten of these patients had documented recurrence. The median time to recurrence was 18 months (95% confidence interval, 9-46 months). Only 1 of the 10 patients showed a radiographic response to systemic therapy. Of 9 patients, 4 had stable disease with somatostatin analogs. The median OS was 143 months (95% confidence interval, 50-143 months). CONCLUSIONS: Renal NENs are rare malignancies affecting mostly middle-age patients, with distant metastasis being common. Approximately one half of patients experience stable disease with somatostatin analogs. The OS usually exceeds 5 years.

Constipation, the sole presentation of primary renal carcinoid tumor: A case report.

Primary renal carcinoid tumors are quite rare. The pathogenesis of these tumors is unknown due to lack of enterochromaffin cells in the kidney. Because of nonspecific clinical manifestations and radiologic features, they are commonly misdiagnosed. Hence, Primary renal carcinoid tumors should be considered in differential diagnosis of any renal mass. In the present case, a 26-year-old woman was presented with a renal mass and constipation. After partial nephrectomy, diagnosis of carcinoid tumor was confirmed.

Primary renal carcinoid: treatment and prognosis.

Primary carcinoid tumors of the kidney are very rare, malignant tumors consisting of neuroendocrine cells. The pathogenesis of renal carcinoid is unclear because neuroendocrine cells are not normally found in adult renal parenchyma. Electron microscopy, immunohistochemistry, octreotide scan, positron emission tomography along with conventional radiographic imaging techniques are used in diagnosis and follow-up. Presenting symptoms usually include flank pain and haematuria. Early stage disease is treated with surgery only. However, randomized trials are lacking because of the very low number of reported cases. Thus, the role of debulking surgery, chemotherapy, radiotherapy, octreotide and targeted therapy in the management of advanced disease remains an open question. In this article the clinicopathologic features and prognosis of this very rare disease along with treatment outcomes of the reported cases are reviewed. In addition, we report a new case of a metastatic primary renal atypical carcinoid tumor treated with octreotide therapy.