Carcinoid tumor arising in a horseshoe kidney

Pathogenesis, diagnosis and treatment of primary renal well-differentiated neuroendocrine tumors: a review of the literature

Neuroendocrine tumors (NETs) are a rare type of neoplasm that originate from neuroendocrine cells and peptide neurons. Primary renal well-differentiated NETs are extremely rare, and only a few cases have been reported worldwide. In this study, we present a new case of primary renal well-differentiated NET at our institution, followed by a literature review. A systematic search was conducted using various search terms to identify relevant literature on primary renal well-differentiated NETs from 2021 to present. The study analyzed the clinical features, age, gender, tumor size, location, gross pathology, light microscopy, and immunohistochemical results of 32 cases of primary renal well-differentiated NETs. The findings suggest that these tumors are rare and have nonspecific clinical and imaging features. The diagnosis heavily relies on immunohistochemical analysis. Primary renal well-differentiated NETs are associated with low malignant potential and a favorable prognosis. Surgical resection is the preferred treatment, and long-term follow-up is necessary to monitor the patient's condition.

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.

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

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.

Primary neuroendocrine tumour of the kidney in an asymptomatic patient involving a multidisciplinary approach

Primary neuroendocrine tumours of the kidney are rare, and their pathophysiology is uncertain; since their discovery in 1966, they have been described only a few times in the literature. We present a case of a well-differentiated neuroendocrine tumour of the kidney in an asymptomatic patient, which required a multidisciplinary approach by the hospital's team, including precise surgical treatment and an effective radiopathological diagnosis. The patient underwent right radical nephrectomy. During follow-up, he remained asymptomatic, and no metastases or complications were identified.

Horseshoe Kidney with Hydronephrosis – Tales of the Unexpected

Horseshoe kidney is an inborn renal fusion anomaly. It is frequently associated with renal stones and infections. The diagnosis is made using imaging methods - ultrasound, X-ray of the abdomen and intravenous pyelography, computed tomography (CT), magnetic resonance imaging (MRI) and radionuclide investigations. The diagnosis sometimes is hard, especially when other abnormalities are present, i.e. hydronephrosis, nephrolithiasis, stenosis of the ureteropelvic junction, etc. The authors present a male patient with horseshoe kidney and unilateral hydronephrosis due to obstruction of the ureteropelvic junction and discuss the diagnosis of horseshoe kidney and the diagnostic approach in such patients.

Primary Carcinoid Tumor of the Renal Pelvis Arising From Intestinal Metaplasia: An Unusual Histogenetic Pathway?

OBJECTIVES

Primary carcinoid tumor of the renal pelvis is a rare neoplasm with few cases reported in the literature. Here we present the clinical and histopathologic findings of a primary carcinoid tumor arising in the left renal pelvis of a horseshoe kidney in a 61-year-old female patient.

MATERIALS AND METHODS

Pathologic features were evaluated with standard hematoxylin and eosin sections and immunohistochemical studies. A literature review was performed to place our case in context to previous reports.

RESULTS

The tumor was associated with intestinal metaplasia with high-grade dysplasia and neuroendocrine hyperplasia. Molecular testing for microsatellite instability and loss of heterozygosity were negative.

CONCLUSIONS

This report portrays a unique presentation of carcinoid tumor arising from intestinal metaplasia of the pelvic urothelium, and supports its histogenesis from urothelial intestinal metaplasia and neuroendocrine hyperplasia.

Carcinoid tumor associated with adjacent dysplastic columnar epithelium in the renal pelvis: A case report and literature review

Carcinoid tumors are well documented in the pulmonary and gastrointestinal systems, but very rare in the urinary tract, especially in the renal pelvis. We report on a 60-year-old female patient who presented with left flank pain and fever. Abdominal computed tomography demonstrated a heterogeneously enhancing mass in the left renal pelvis and a stone at the left proximal ureter. Multiple parenchymal lesions were also observed, which were identified as uneven caliectasis displaying air-fluid levels and renal parenchymal atrophy. The patient underwent simple nephro-ureterectomy. Macroscopically, a polypoid mass was observed in the renal pelvis. Microscopically, the tumor revealed acinar, tubular, and solid pattern and was composed of small, monotonous and hyperchromatic cells. Lining epithelia in renal pelvis and ureter revealed columnar epithelia with dysplastic change. The tumor cells were positive for chromogranin A, synaptophysin, CD56, and focally positive for cytokeratin. Immunohistochemical staining of synaptophysin and chromogranin A highlighted the neuroendocrine cells in the columnar epithelium. Ki-67 (1:50; MIB-1) labeling index was less than 1% in the area with highest uptake. We report here a case of carcinoid tumor of the renal pelvis that was associated with adjacent dysplastic columnar epithelium.

Renal carcinoid tumor with liver metastasis followed up postoperatively for 9 years

Background

We describe a case of renal carcinoid tumor with liver metastasis followed up postoperatively for 9 years.

Case presentation

A 33-year-old man presented with left flank dull ache. On the abdominal computed tomography, a solid renal mass in the upper portion of the left kidney was detected. The patient had no other abnormal findings, such as suspected distant metastasis or lymph node metastasis. Radical nephrectomy was performed on 14/9/2005. Histological examination and immunohistochemical staining confirm primary renal carcinoid tumor. 9 years after radical nephrectomy, computed tomography of the abdomen demonstrated a 2 cm × 1.8 cm cyst mass in the right liver. Similar pathologic characteristics were found between the renal carcinoid tumor and liver tumor.

Conclusions

We present a primary renal carcinoid tumor with liver metastasis 9 years after radical nephrectomy. With literature review, renal carcinoid tumors exhibit heterogenous behavior.

Primary carcinoid tumour of the kidney: a review of the literature

Context. Primary renal carcinoid tumours are rare. Their pathogenesis is unknown and the clinical presentation is similar to other renal tumours thus posing diagnostic dilemmas for clinicians. Objectives. To review the literature for case reports of primary renal carcinoids. Methods. Literature was extensively searched for case reports for primary renal carcinoids. Reports of metastatic carcinoids to the kidneys were excluded. Results. Approximately less than 90 cases of primary carcinoid tumours of the kidney have been reported in the literature. A total of 29 cases of primary renal carcinoids were reviewed. The mean age of presentation was 48 years (range 29–75) with both right kidney (48.3%) and left kidney (44.8%) being equally affected. 28.6% of the cases reviewed were diagnosed as an incidental finding. The mean followup time was 20 months with 73.1% of patients without evidence of disease after surgical treatment (radical or partial nephrectomy). Primary carcinoid tumours of the kidney are often well differentiated tumours. They are often misdiagnosed because of their rarity and similar presentation with other renal tumours. Conclusions. Primary carcinoid tumours of the kidney are rare tumours with an indolent course with frequent metastasis. Metastatic work up and followup is required in their management.

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.

Primary neuroendocrine tumors of the kidney: morphological and molecular alterations of an uncommon malignancy

Primary neuroendocrine (NE) tumors of the kidney (PNRTs) are rare and frequently mistaken for other renal and urothelial cancers. We evaluated morphological and molecular findings of 11 PNRTs classified according to the World Health Organization classification of lung NE tumors. Patients included 5 men and 6 women with a median age of 50 years. These tumors occurred in the left (5/11), right (3/11), and horseshoe (1/11) kidney. The histologic patterns were predominantly solid, trabecular, and pseudoglandular. Lymphovascular invasion and calcification were found in 3 and 1 cases, respectively. There were 2 atypical and 9 typical carcinoids. At the time of surgery, 2 patients with atypical carcinoids had hepatic metastasis, and 1 of the typical carcinoid patients had lymph node metastasis. All cases showed <1% proliferative rate, except 2 cases with hepatic metastasis, which showed 3% to 5% with MIB1/Ki-67 immunostaining. Immunostainings were frequently positive for synaptophysin, chromogranin, CD56, CD99, and neuron-specific enolase. Follow-up data (average 4 years) were available for 6 patients. Two patients with distant metastasis were alive with disease, and four patients with no metastasis were alive without disease. We evaluated the association of PNRT and loss of heterozygosity (LOH) on chromosome 3p21 and found LOH in 2 of 3 cases. However, the comparative genomic hybridization study (2/2) did not demonstrate significant chromosomal imbalances. We conclude that PNRTs are positive for NE markers and may have LOH on chromosome 3p21. PNRTs should be classified as NE tumors in other sites, and proliferative rate can be an indicator of aggressive behavior/metastasis.

Primary renal carcinoid tumour with inferior vena caval tumour thrombus

Carcinoid tumours, most frequently reported in the gastrointestinal and respiratory tracts, are exceedingly rare primary renal cancers. Few cases have been published to date. To our knowledge, we report the first case of a primary carcinoid tumour of the kidneys involving the inferior vena cava. We treated a 58-year-old woman with an open radical nephrectomy and cavotomy with thrombectomy. We describe the presentation, investigations and pathology results. We discuss the current experience with carcinoid tumours as a literature review relating to the diagnosis of the disease and the prognosis of patients with this neoplasm. Localized carcinoid tumours of the kidneys, including those involving the vena cava, can be successfully treated with surgical excision.

Synchronous primary carcinoid tumor and primary adenocarcinoma arising within mature cystic teratoma of horseshoe kidney: a unique case report and review of the literature

Background

Malignant transformation of mature cystic teratoma is a rare complication. While any of the constituent tissues of a teratoma has the potential to undergo malignant transformation, squamous cell carcinoma is the most commonly associated malignancy. Renal carcinoid tumors are rare and frequently associated with horseshoe kidney and renal teratoma. Renal teratoma rarely presents together with carcinoid tumor or adenocarcinoma. To the best of our knowledge, there has never been a report of renal teratoma coexisting with both carcinoid tumor and adenocarcinoma.

Methods

Here, we present a unique and first case of synchronous primary carcinoid tumor and moderately differentiated adenocarcinoma arising within mature cystic teratoma of horseshoe kidney in a 50-year-old female. Lumbar spine X-ray, done for her complaint of progressive chronic low back pain, accidentally found a large calcification overlying the lower pole of the right kidney. Further radiologic studies revealed horseshoe kidney and a large multiseptated cystic lesion immediately anterior to the right renal pelvis with central calcification and peripheral enhancement. She underwent right partial nephrectomy.

Results

Macroscopically, the encapsulated complex solid and multiloculated cystic tumor with large calcification, focal thickened walls and filled with yellow-tan gelatinous material. Microscopically, the tumor showed coexistent mature cystic teratoma, moderately differentiated adenocarcinoma and carcinoid tumor. Immunohistochemically, alpha-methylacyl-coenzyme A-racemase, calretinin, CD10 and thyroid transcription factor-1 were negative in all the three components of the tumor. The teratomatous cysts lined by ciliated epithelium showed strong staining for cytokeratin 7 and pancytokeratin, and those lined by colonic-like epithelium showed strong staining for CDX2, cytokeratin 20 and pancytokeratin, but both were negative for calretinin. Additionally, the teratomatous cyst wall showed strong staining for smooth muscle actin, and weak staining for carbonic anhydrase IX, CD99, chromogranin and synaptophysin. The adenocarcinoma component was strongly positive for cytokeratin 7 and pancytokeratin, weakly positive for synaptophysin and CD56, and negative for carbonic anhydrase IX, CD99, CDX2, chromogranin, cytokeratin 20 and smooth muscle actin. The carcinoid tumor component was strongly positive for CD56, chromogranin and synaptophysin, weakly positive for pancytokeratin, and negative for carbonic anhydrase IX, CD99, CDX2, cytokeratin 7, cytokeratin 20 and smooth muscle actin. She received no adjuvant therapy and is alive without evidence of disease six months after diagnosis and surgery.

Conclusion

This unique and first case herein presented with synchronous primary carcinoid tumor and primary adenocarcinoma arising within mature cystic teratoma of horseshoe kidney emphasizes the need for thorough sectioning and entire submission for histologic evaluation of mature cystic teratomas, in order to avoid missing multiple additional histogenetically distinct neoplasms.

Surgical treatment of a rare primary renal carcinoid tumor with liver metastasis

Background

Carcinoid tumors are characteristically low grade malignant neoplasms with neuroendocrine differentiation that arise in various body sites, most commonly the lung and gastrointestinal tract, but less frequently the kidneys, breasts, ovaries, testes, prostate and other locations. We report a case of a carcinoid of renal origin with synchronous single liver metastases on radiological studies.

Case presentation

A 45 year-old patient who presented with abdominal pain was found on CT scan to have lesions in the right ovary, right kidney, and left hepatic lobe. CA-125, CEA, and CA 19-9 were within normal limits, as were preoperative liver function tests and renal function. Biopsy of the liver mass demonstrated metastatic neuroendocrine tumor. At laparotomy, the patient underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy, radical right nephrectomy with lymphadenectomy, and left hepatectomy. Pathology evaluation reported a right ovarian borderline serous tumor, well-differentiated neuroendocrine carcinoma of the kidney (carcinoid) with 2 positive retroperitoneal lymph nodes, and a single liver metastasis. Immunohistochemistry revealed that this lesion was positive for synaptophysin and CD56, but negative for chromogranin as well as CD10, CD7, and CD20, consistent with a well-differentiated neuroendocrine tumor. She is doing well one year after her initial surgery, with no evidence of tumor recurrence.

Conclusion

Early surgical intervention, together with careful surveillance and follow-up, can achieve successful long-term outcomes in patients with this rare malignancy.