Primary renal carcinoid tumor with liver metastases detected with somatostatin receptor imaging

Well‑differentiated 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.

Neuroendocrine neoplasms of the genitourinary tract in adults: cross-sectional imaging spectrum

Neuroendocrine (NE) neoplasms of the genitourinary (GU) tract in adults are rare tumors with distinct histopathology and variable biological behavior and imaging findings. They may be primary or metastatic in origin. The spectrum of primary GU tract NE neoplasms includes carcinoid, small cell carcinoma, large cell NE carcinoma, and paraganglioma. The tumors commonly show positivity to specific immunohistochemical markers and characteristic dense-core granules at the ultra-structural level. Although imaging findings are nonspecific and accurate differentiation from the more common malignancies of the individual organs is not possible, cross-sectional imaging modalities play an important role in the diagnosis, staging, and surveillance of these tumors. Somatostatin receptor scintigraphy (octreotide scan) may be useful in the detection and treatment of metastatic disease in select patients. Knowledge of the various NE tumors of the adult GU tract and familiarity with their pathological and imaging findings permit optimal patient management.

Successful Repeated Peptide Receptor Radionuclide Therapies in Renal Neuroendocrine Tumor With Osseous Metastasis

Renal neuroendocrine tumor (NET) is an extremely rarely occurring disease. The sporadic reports in the literature are mostly case reports, or less commonly small studies. In cases of metastatic disease from renal NET, there are no established therapies. We are reporting our experience with a patient with extensive osseous infiltration of a renal NET, who was successfully treated with peptide receptor radionuclide therapy (PRRT) using Lu-DOTATATE. In a period of 10 years, the patient underwent in total 12 cycles of PRRT with a cumulative dose of 81 GBq. All therapies were unproblematic and well tolerated.

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.

Primary renal carcinoid tumor: A radiologic review

Carcinoid tumor is the classic famous anonym of neuroendocrine neoplasms. Primary renal carcinoid tumors are extremely rare, first described by Resnick and colleagues in 1966, with fewer than a total of 100 cases reported in the literature. Thus, given the paucity of cases, the clinical and histological behavior is not well understood, impairing the ability to predict prognosis. Computed tomography and (occasionally) octreotide studies are used in the diagnosis and followup of these rare entites. A review of 85 cases in the literature shows that no distinctive imaging features differentiate them from other primary renal masses. The lesions tend to demonstrate a hypodense appearance and do not usually enhance in the arterial phases, but can occasionally calcify. Octreotide scans do not seem to help in the diagnosis; however, they are more commonly used in the postoperative followup. In addition, we report a new case of primary renal carcinoid in a horseshoe kidney.

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.

Renal neuroendocrine tumors

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.

Neuroendocrine tumours of the urinary system and male genital organs: clinical significance

Two basic types of neuroendocrine (NE) tumours with diverse clinicopathological features and outcome are identified in the urinary system and male genital organs: carcinoid tumour and neuroendocrine carcinoma. Carcinoid, a rare tumour, occurs in the kidney, bladder, prostate and testis. It is morphologically, histochemically, immunohistochemically and ultrastructurally similar to its counterpart in other organs, such as lung or gastrointestinal tract. Metastases can be detected at the initial evaluation, although they have been reported up to several years after removal, emphasizing the need for a long-term follow-up. NE carcinoma occurs in the kidney, bladder and prostate, and includes small cell carcinoma (SCC) and large cell NE carcinoma (LCNEC), the latter being exceedingly rare. Both show the morphology and immunophenotype of NE carcinoma originating in other organs. Although the occurrence is rare, it is highly aggressive.

Renal neuroendocrine tumours: a clinicopathological study

OBJECTIVES

To report cases of primary neuroendocrine tumours (NETs) of the kidney, including carcinoid tumour, large cell neuroendocrine carcinoma (LCNEC) and small cell carcinoma (SCC), which show a wide range of NE differentiation and biological behaviour, and are exceedingly rare.

PATIENTS AND METHODS

The clinicopathological features of all nine renal NETs diagnosed during a 7-year period were reviewed.

RESULTS

Six carcinoids, two SCC and one LCNEC were identified from 2780 kidney tumours. No patient had carcinoid syndrome or other NE symptoms. Three of six carcinoids and no SCC/LCNEC arose in horseshoe kidneys. The mean size of the six carcinoids and three SCC/LCNEC was 4.8 cm and 12.2 cm, respectively. No carcinoid had tumour necrosis or mitosis. By contrast, three SCC/LCNEC had extensive tumour necrosis and brisk mitosis. All renal NETs were positive for synaptophysin but were variably positive for chromogranin and CD56. Three of six carcinoid tumours were confined to the kidney, and four of five patients were disease-free at a mean (range) of 26 (6-74) months. One patient with nodal metastases has had no recurrence and another died with liver metastases. Three patients with SCC/LCNEC each presented with locally advanced disease and extensive lymphadenopathy; two of them died from distant metastasis or local tumour progression, and the third is currently alive with disease.

CONCLUSIONS

Various NETs can occur in the kidney, but rarely. Renal carcinoids have a variable clinical course; SCC and LCNEC are associated with poor clinical outcomes. The diagnosis of NETs, especially LCNEC, requires awareness of their rare occurrence and prudent use of immunohistochemical NE markers.

Anatomic and functional imaging of metastatic carcinoid tumors

Carcinoid tumors are a fascinating group of neuroendocrine neoplasms that develop either sporadically or as part of an inheritable syndrome. Many tumors arise in the bronchopulmonary or gastrointestinal tract, but a neuroendocrine tumor can arise in almost any organ. The tumors have varied malignant potential depending on the site of their origin, and the clinical manifestations often are nonspecific. Metastases may be present at the time of diagnosis, which often occurs at a late stage of the disease. Imaging plays a pivotal role in the localization and staging of neuroendocrine tumors and in monitoring the treatment response. Imaging is often challenging, and a combination of anatomic and functional techniques is usually required, depending on the tumor type and location. Techniques include ultrasonography, barium studies, endoscopy, computed tomography, magnetic resonance imaging, somatostatin receptor scintigraphy, iobenguane scintigraphy, and, in select cases, positron emission tomography. Coregistration of structural and functional images is often of incremental value for accurate localization of the primary tumor and any meta-static disease. Radiologists must understand the contribution of each imaging modality in the assessment of different neuroendocrine tumors. In addition, knowledge of the optimal technique for each radiologic and radionuclide imaging examination is essential. Familiarity with the protean imaging appearances of both primary and metastatic disease is essential for accurate staging, treatment monitoring, and surveillance. Finally, an understanding of the wide variety of treatment options for patients with carcinoid tumors is vital for optimal management.

Primary Carcinoid Tumors of the Kidney

PURPOSE

We describe in detail the features of carcinoid tumors of the kidney. We evaluated possible prognostic factors.

MATERIALS AND METHODS

An extensive search was performed in the medical literature regarding primary carcinoid tumors of the kidney. Epidemiological, clinical, diagnostic, histopathological, therapeutic and prognostic data were evaluated. Several potential risk factors were compared with the incidence of metastases and clinical outcome of the patients.

RESULTS

A total of 56 case reports were reviewed. Median patient age was 49 years. Horseshoe kidneys were present in 17.8% of cases. Incidental diagnosis was made in 28.6% of patients. The most common symptom was abdominal or flank pain and neuroendocrine syndromes occurred with only 12.7% of primary renal carcinoid tumors. Of the patients 73.6% presented with tumors larger than 4 cm. Metastases were present in 45.6% of patients at initial diagnosis and almost 60% with tumors greater than 4 cm had metastases.

CONCLUSIONS

Renal carcinoid is the second most prevalent genitourinary carcinoid in each sex, following testicular carcinoids in men and ovarian tumors in women. Significant adverse prognostic factors include age greater than 40 years, tumor size greater than 4 cm, purely solid tumors on the cut surface, mitotic rate higher than 1/10 high power fields, metastasis at initial diagnosis and tumors extending throughout the renal capsule.

Carcinoid tumors of the urinary tract and prostate

CONTEXT

Carcinoid tumors are exceedingly rare in the genitourinary tract and may occur in the kidney, urinary bladder, urethra, or prostate.

OBJECTIVE

To review the clinical and pathologic features of carcinoid tumors occurring in the urinary tract and prostate.

DATA SOURCES

We searched the English language literature using MEDLINE and Ovid.

CONCLUSIONS

Carcinoid tumors of the urinary tract and prostate share similar morphologic features with their counterparts in other organs. The differential diagnosis includes metastatic carcinoid tumor, paraganglioma, and nested variants of urothelial and prostatic carcinomas. Correlation of the clinical presentation and histopathologic features (including the immunohistochemical profile) will ensure accurate diagnosis of these rare tumors.

Gastrointestinal carcinoids: the evolution of diagnostic strategies

Carcinoid tumors are rare, often insidious neoplasms arising from neuroendocrine cells. The majority arise in the gastrointestinal system, and are often incidentally found during investigation, although some may present as an emergency bleed or perforation. The prosaic symptoms of flushing, diarrhea, and sweating are often overlooked; thus, the diagnosis is usually much delayed and the tumor is advanced at presentation. This diagnostic delay renders effective management difficult and adversely affects outcome. This overview provides a current assessment of the evolution of the diagnostic techniques available to establish an accurate biochemical (5-hydroxyindole-3-acetic acid and chromogranin A) and topographic diagnosis (octreoscan, radio-labeled metaidobenzylguanidine, computerized tomography, magnetic resonance imaging, positron emission tomography, enteroclysis, endoscopic ultrasound, enteroscopy, capsule endoscopy, and angiography) of carcinoid tumors. The utility and shortcomings of the respective modalities available are evaluated. Although considerable advances have been made in establishing the diagnosis of carcinoid tumors and in defining the topography of metastatic disease, the major limitation is the inability to establish an early and timely diagnosis before the advent of metastatic disease.

Carcinoid tumor arising in a horseshoe kidney

Carcinoid tumors are common neoplasms developing in gastrointestinal and respiratory tract. They are rarely found in the kidney. To date, approximately 40 cases of primary renal carcinoid tumors have been reported, with less of a third of them occurring within a horseshoe kidney. These cases appear to have a better prognosis, even in the presence of distant metastases, compared to those arising in normal kidneys.

Multifocal Renal Carcinoid Tumor Arising in Horseshoe Kidney with Metastases to the Thyroid

Primary renal carcinoid tumor is a rare tumor of the kidney. Less than 40 cases of primary and metastatic renal carcinoids have been reported. There is a strong association of renal carcinoid tumors with horseshoe kidneys [1, 2]. The radiographic appearance is non-specific and overlaps that of renal cell carcinoma. Histopathologic differentiation between these two entities is essential because the treatment and prognosis are entirely different. We report a unique case of multifocal carcinoid tumor within a horseshoe kidney with metastases to the thyroid gland. It has been postulated that the renal carcinoid horseshoe subtype carried a more favorable prognosis; however, our case with multifocal involvement and distant metastases suggests the possibility for a more aggressive course.