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

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 Small Cell Carcinoma of the Kidney: A Case Study with Emphasis on Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography Findings

Small cell carcinoma (SCC) of the kidney is included in extrapulmonary SCC which is a group of extremely rare but highly aggressive cancers. There have been only a few case reports and small retrospective series in the literature describing the malignancy in kidneys. Most of the published reports describe the entity as a variant mixed with other tumor subtypes such as urothelial carcinoma, adenocarcinoma, and squamous cell carcinoma. Pure-form SCC in kidneys is exceedingly rare. Fluorodeoxyglucose positron emission tomography-computed tomography plays an essential role in the accurate staging evaluation of this cancer.

Extrapulmonary Neuroendocrine Carcinomas: Current Management and Future Perspectives

Neuroendocrine carcinomas (NECs) are poorly differentiated and highly aggressive epithelial neuroendocrine neoplasms. The most common primary site is the lung, but they may arise in every organ. Approximately 37% of extrapulmonary NECs (EP-NECs) occur in the gastroenteropancreatic (GEP) tract, followed by the genitourinary (GU) system and gynecological tract. As a result of their rarity, there is scant evidence to guide treatment recommendations, and a multidisciplinary approach is essential for the management of such patients. Platinum-based chemotherapy currently represents the standard of care for EP-NECs of any site, mirroring the management of small-cell lung cancer (SCLC), but further approaches are still under investigation. Indeed, ongoing trials evaluating targeted therapies, immune checkpoint inhibitors (ICIs), and radionuclide therapy could provide potentially breakthrough therapeutic options. Given the relative dearth of evidence-based literature on these orphan diseases, the aim of this review is to provide an overview of the pathology and current treatment options, as well as to shed light on the most pressing unmet needs in the field.

Small-cell neuroendocrine tumor of the bladder: Unexpected long-term survival with carboplatin-etoposide therapy in a patient with metastatic stage disease

Neuroendocrine small-cell bladder cancer is an extremely rare and aggressive entity, it constitutes <1% of all bladder malignancies. The small-cell neuroendocrine histological variant has a worse prognosis than the classical subtypes. A case of a 53-year-old female consulting with gross hematuria is presented. Cystoscopy revealed a solid aspect lesion involving the posterior wall and dome that was resected. Histopathological findings showed small-cell pure variant carcinoma, high grade, with lymph, vascular, and perineural infiltration, infiltrating the muscle layer. The extension study made by hole body computed tomography scan, showed evidence of multiple lymph nodes and multiple visceral radiological involvements, with pulmonary, hepatic, and peritoneal implants. More than 10 years later, after receiving nine cycles of carboplatin-etoposide remains in complete remission and without radiological evidence of the disease. This is, to our knowledge, one of the longest disease-free survival cases in metastatic small-cell bladder cancer published nowadays.

Imaging of neuroendocrine neoplasms of the male GU tract

Male genitourinary neuroendocrine neoplasms (GU-NENs) are rare, without any definite imaging characteristics. The WHO classified neuroendocrine neoplasms in the 2016 classification of the tumors of the urinary tract and genital organs along with other GU tumors; however, no pathologic grading system is available as published for gastroenteropancreatic neuroendocrine neoplasms. Often a multimodality approach using cross-sectional imaging techniques, such as molecular imaging and histopathology are implemented to arrive at the diagnosis. This article provides a review of the pathology and imaging features of the male GU-NENs.

Classifying Pulmonary and Urinary High-grade Neuroendocrine Carcinoma by CK7 Immunohistochemistry

High-grade neuroendocrine carcinoma (HGNEC) is subclassified into small cell carcinoma (SmCC) and large cell neuroendocrine carcinoma (LCNEC). Although both are clinically aggressive, the SmCC and LCNEC need to have different treatment strategies, and accurate pathologic diagnosis is challenging. We studied a large retrospective cohort (186 cases) of HGNEC of bladder and lung to investigate the abundance of cytokeratin (CK) 7 expression and staining pattern in SmCC and LCNEC. Overall, the pulmonary and urinary HGNEC exhibited several different CK7 staining patterns, including negative staining (n=28), dot-like staining (n=73), partial membranous staining (n=26), and complete membranous staining (n=60). Overall, 88.9% (44/49) of pulmonary SmCC and 88.0% (44/50) of urinary SmCC showed negative or dot-like patterns for CK7, while 90.8% (59/65) of pulmonary LCNEC and 72.7% (16/22) of urinary LCNEC showed partial or complete membranous patterns for CK7 (χ 2 =105.05, P <0.0001). The distinct staining patterns were also present in those mixed SmCC and LCNEC. In addition, the specimen types or fixation did not affect CK7 staining patterns. In conclusion, CK7 has a high differential value for SmCC and LCNEC and could help guide personalized treatment for patients.

Neuroendocrine Neoplasms of the Female Genitourinary Tract: A Comprehensive Overview

Simple Summary

Primary neuroendocrine neoplasms (NENs) are a rare, heterogeneous group of tumors that include well-differentiated neuroendocrine tumors, poorly differentiated neuroendocrine carcinoma, and paraganglioma. NENs in the urinary tract are observed in <0.05% of individuals, in whom the bladder is the most common site. In this review, we described the epidemiology, pathogenesis, imaging, staging, and management of the genitourinary NENs.

Abstract

Primary neuroendocrine neoplasms are a rare heterogeneous group of tumors that include well-differentiated neuroendocrine tumors, poorly differentiated neuroendocrine carcinoma, and paraganglioma. An extensive literature search was used to compile the data regarding epidemiology, pathogenesis, imaging features, and management of the urinary system NENs. We also included the updated staging of the NENs at various locations of the urinary system.

Urinary Large Cell Neuroendocrine Carcinoma: A Clinicopathologic Analysis of 22 Cases

Large cell neuroendocrine carcinoma (LCNEC) of the urinary tract is a rare disease. We present a relatively large retrospective cohort of urinary LCNEC, 20 from the urinary bladder, and 2 from the ureter, from a single institution. The patients included 16 men and 6 women with a median age of 74.5 years. Most LCNEC presented at an advanced stage with tumors invading the muscularis propria and beyond (21/22). Eight cases were pure LCNEC, while 14 cases were mixed with other histologic types, including conventional urothelial carcinoma (n=9), carcinoma in situ (n=7), small cell carcinoma (n=6), and urothelial carcinoma with glandular (n=3) features. Most LCNEC expressed neuroendocrine markers synaptophysin (22/22), chromogranin (13/16), CD56 (7/7), TTF1 (8/8), and INSM1 (2/3). They were negative for common urothelial markers including HMWCK (0/3), p40/p63 (0/6), CK20 (0/10), and had variable GATA3 staining (4/8). Ki-67 stained 25% to nearly 100% tumor cell nuclei. Patient survival was associated with cancer stage, and pure LCNEC showed worse survival than mixed LCNEC. Compared with small cell carcinoma at similar stages from a prior study, LCNEC had a worse prognosis only when patients developed metastatic disease. For organ-confined LCNEC, neoadjuvant chemotherapy followed by radical resection is the treatment option to achieve long-term survival.

Expression of novel neuroendocrine marker insulinoma-associated protein 1 (INSM1) in genitourinary high-grade neuroendocrine carcinomas: An immunohistochemical study with specificity analysis and comparison to chromogranin, synaptophysin, and CD56

Confirmation of genitourinary high-grade neuroendocrine carcinomas (GU-HGNECs) often requires immunohistochemical staining. Here we evaluated a novel neuroendocrine marker, insulinoma-associated protein 1 (INSM1), in GU-HGNECs with comparison to chromogranin, synaptophysin and CD56. Immunohistochemical expression of INSM1, chromogranin, synaptophysin, and CD56 was evaluated in 39 GU-HGNECs using full tissue sections [4 in kidney, 28 in urinary bladder, and 7 in prostate; 31 small cell carcinomas (SmCCs), 6 large cell neuroendocrine carcinomas (LCNECs), 2 mixed SmCC-LCNECs]. In 33 SmCCs/components, INSM1 showed similar sensitivity (93.9 %) to chromogranin (87.8 %), synaptophysin (93.9 %) and CD56 (87.8 %), and stained a similar percentage of tumor cells (52 %) to chromogranin (49 %) and CD56 (52 %), but lower than synaptophysin (87 %) (p < 0.0001). In 8 LCNECs/components, INSM1 is similar to chromogranin, synaptophysin or CD56 in sensitivity (62.5 %, 62.5 %, 75 %, 62.5 %, respectively) and the mean percentage of positively stained tumor cells (21 %, 44 %, 48 %, 37 %, respectively). INSM1 is more sensitive for SmCCs than LCNECs (93.9 % vs. 62.5 %, p = 0.015). INSM1 showed 97.4 % specificity upon analyzing 273 genitourinary non-neuroendocrine tumors on tissue microarrays. Our study indicates that INSM1 is a sensitive marker for genitourinary HGNECs with high specificity. For genitourinary SmCCs, INSM1 shows similar sensitivity to chromogranin, synaptophysin and CD56 but stains a lower percentage of tumor cells than synaptophysin. For genitourinary LCNECs, INSM1 showed similar sensitivity to chromogranin, synaptophysin and CD56. INSM1 is more sensitive for genitourinary SmCCs than LCNECs. Our result and literature review indicate that whether INSM1 is more sensitive than conventional neuroendocrine markers for HGNECs depends on the tumor primary sites.

Morphologic, Molecular and Clinical Features of Aggressive Variant Prostate Cancer

The term aggressive variant prostate cancer (AVPCa) refers to androgen receptor (AR)-independent anaplastic forms of prostate cancer (PCa), clinically characterized by a rapidly progressive disease course. This involves hormone refractoriness and metastasis in visceral sites. Morphologically, AVPCa is made up of solid sheets of cells devoid of pleomorphism, with round and enlarged nuclei with prominent nucleoli and slightly basophilic cytoplasm. The cells do not show the typical architectural features of prostatic adenocarcinoma and mimic the undifferentiated carcinoma of other organs and locations. The final diagnosis is based on the immunohistochemical expression of markers usually seen in the prostate, such as prostate-specific membrane antigen (PSMA). A subset of AVPCa can also express neuroendocrine (NE) markers such as chromogranin A, synaptophysin and CD56. This letter subset represents an intermediate part of the spectrum of NE tumors which ranges from small cell to large cell carcinoma. All such tumors can develop following potent androgen receptor pathway inhibition. This means that castration-resistant prostate cancer (CRPCa) transdifferentiates and becomes a treatment-related NE PCa in a clonally divergent manner. The tumors that do not show NE differentiation might harbor somatic and/or germline alterations in the DNA repair pathway. The identification of these subtypes has direct clinical relevance with regard to the potential benefit of platinum-based chemotherapy, poly (ADP-ribose) polymerase inhibitors and likely further therapies.

Prospective molecular and morphological assessment of testicular prepubertal-type teratomas in postpubertal men

In 2016, the World Health Organization classification system of testicular tumors included the new entity prepubertal-type teratoma based on its morphological and molecular profile, and the realization that these tumors may occur in postpubertal men. For treatment and prognostic purposes, it is important to distinguish prepubertal-type teratoma from the usual postpubertal-type teratoma, because the former is benign unlike the latter. The distinction may be challenging. In this study, we investigated clinical, morphological, and molecular criteria for distinguishing prepubertal-type teratoma from postpubertal-type teratoma in a prospective series of pure testicular teratomas. All cases of pure teratoma in postpubertal men assessed at Barts Health NHS Trust or in consultation since the introduction of routine investigation of chromosome 12p status in 2010 were reviewed. Morphological features suggestive of prepubertal-type teratoma were observed in 14 out of 35 cases. All underwent molecular testing and none displayed 12p amplification. Mean tumor size was 16 mm (range 7-28 mm). None had associated germ cell neoplasia in situ or significant atrophy. Four incorporated a well-differentiated neuroendocrine tumor, 1-2 mm in size. Of the ten patients with follow-up information, none have recurred or metastasized. Twenty-one of the 35 cases were diagnosed as postpubertal-type teratoma, mean tumor size 40 mm (range 6-90 mm). One case underwent molecular testing: a tumor of pure skeletal muscle differentiation and possessed 12p amplification. Three cases presented with clinical metastases. Eight cases contained immature areas, ten cases had associated germ cell neoplasia in situ, and 17 cases had severe atrophy of the parenchyma. One case with neither germ cell neoplasia in situ nor atrophy showed necrosis. We conclude that both morphological and molecular features are of help in differentiating prepubertal-type teratoma from postpubertal-type teratoma. In nearly all postpubertal-type teratomas, molecular testing was unnecessary, and merely confirmed the morphological impression in the prepubertal-type teratomas. Our study confirmed the high incidence of well-differentiated neuroendocrine tumors in the prepubertal-type.

Primary small cell carcinoma of the urinary bladder

Small cell carcinoma of the urinary bladder (SCCB) is an extremely rare but aggressive tumour constituting less than 0.7% of all urinary bladder tumours. It is often misdiagnosed as transitional cell carcinoma, owing to the similarities in presentation. Diagnosis of SCCB is based on the WHO criteria for small cell lung carcinoma. A 58-year-old man who had presented with haematuria and burning micturition for 3 months was initially diagnosed as high-grade muscle-invasive urothelial carcinoma based on the TURBT specimen. The patient was put on neoadjuvant chemotherapy, but presented again with haematuria and back pain after 3 months. Imaging studies showed a lesion in the posterolateral wall of the urinary bladder, along with partial collapse and anterior wedging of L1 vertebra. He underwent TURBT, and on the basis of histopathology and immunohistochemistry, a diagnosis of primary SCCB bladder with vertebral metastasis was made.

Robot-assisted Radical Prostatectomy Due to a Primary Carcinoid Prostatic Tumor in a Three-Year-Old Child: A Case Report

We present an extremely rare case of a 3-year-old child with a primary carcinoid tumor of the prostate. A 3-year-old boy presented with failure to thrive, constipation, recurrent respiratory tract infections, and pain in the genital area. His karyotype was normal and cystic fibrosis and coeliac disease were excluded prior to further investigation. An abdominopelvic computed tomography scan revealed a prostatic mass. Transrectal ultrasound-guided prostate biopsy was therefore performed and pathological examination revealed a carcinoid tumor. A robotic radical prostatectomy was performed. As this is an innovative surgical approach, we describe the surgical technique used.

Focal Neuroendocrine Differentiation of Conventional Prostate Adenocarcinoma as a Prognostic Factor after Radical Prostatectomy: A Systematic Review and Meta-Analysis

The biologic and prognostic value of focal neuroendocrine differentiation (NED) in conventional prostate adenocarcinoma (PC) patients who undergo radical prostatectomy (RP) remains controversial. In this systematic review and meta-analysis, we assessed the association of focal NED in conventional PC with oncological outcomes after RP. A literature search using PubMed, Scopus, Web of Science, and Cochrane Library was conducted on December 2018 to find relevant studies according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. We used a fixed-effect model to analyze the impact of focal NED in RP specimen on progression-free survival defined by biochemical recurrence (BCR). A total of 16 studies with the outcomes of disease progression and survival were eligible. No patient in these studies received androgen deprivation therapy prior to RP. Eleven studies found no significant correlation between focal NED and outcomes of interest, while five studies reported a significant association of focal NED assessed by immunohistochemical chromogranin A or serotonin staining with BCR or survival. Focal NED was associated with higher BCR rates after RP with a pooled HR of 1.39 (95% CI 1.07‒1.81) in five studies. No heterogeneity was reported in this analysis (I² = 21.7%, p = 0.276). In conclusion, focal NED in conventional PC is associated with worse prognosis after RP. Its presence should be reported in pathologic reports and its true clinical impact should be assessed in well-designed prospective controlled studies.

Unusual Sites of High-Grade Neuroendocrine Carcinomas: A Case Series and Review of the Literature

Case series

Patient: Female, 29 • Female, 69 • Female, 52 • Female, 71 • Male, 62 • Female, 67

Final Diagnosis: Neuroendocrine carcinoma

Symptoms: Abdominal pain

Medication: —

Clinical Procedure: —

Specialty: Oncology

Impact of squamous and/or glandular differentiation on recurrence and progression following transurethral resection for non-muscle invasive urothelial carcinoma of bladder

The aim of the present study was to investigate the impact of squamous and/or glandular differentiation on the recurrence and progression in patients with nonmuscle invasive urothelial carcinoma of bladder (NMIUCB) following transurethral resection (TURBT). A total of 869 patients with NMIUCB who had been treated with TURBT at The Second Hospital of Tianjin Medical University (Tianjin, China) between January 2006 and January 2011 were retrospectively selected for the present analysis. Associations among squamous and/or glandular differentiation with other clinical and pathological features were assessed by the χ2 test. Recurrence-free survival (RFS) and progression-free survival (PFS) curves were estimated using the Kaplan-Meier method. Univariate and multivariate analyses were performed through a Cox's proportional hazards regression model. Among the 869 patients, 232 (26.7%) patients had squamous and/or glandular differentiation. High grade tumors were more common in patients with squamous and/or glandular differentiation compared with those with pure urothelial carcinoma of bladder (P<0.001). Associations between age (P=0.115), sex (P=0.184), tumor size (P=0.223), tumor multiplicity (P=0.108), pathological tumor stage (P=0.909) and squamous and/or glandular differentiation were not observed to be statistically significant. There was a significant tendency towards higher recurrence rate and shorter RFS time in patients with squamous and/or glandular differentiation. However, no statistically significant differences were observed in progression rate and PFS between the two groups. The multivariate Cox regression analysis, identified squamous and/or glandular differentiation as an independent prognostic predictor of recurrence (hazard ratio =1.46, 95% confidence interval=1.10–1.92, P=0.008). In the present study, the presence of squamous and/or glandular differentiation was associated with a higher recurrence rate and shorter RFS time in patients with NMIUCB. Squamous and/or glandular differentiation is therefore an independent prognostic predictor of recurrence.

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.

An Unusual Case of Resistant Hypokalaemia in a Patient with Large Bowel Obstruction Secondary to Neuroendocrine Carcinoma of the Prostate

Neuroendocrine Carcinoma of the Prostate (NECP) is rare and only few cases have been reported, constituting less than 0.5% of prostatic malignancies. We report a rare case of large bowel obstruction from NECP posing a further challenge in management due to resistant hypokalaemia. A 70-year-old man presented with clinical signs of large bowel obstruction who was known to have prostatic carcinoma three years ago, treated initially with hormone therapy then chemoradiation. The blood profile showed a severe hypokalaemia and CT scan revealed liver and lung metastases apart from confirming large bowel obstruction from local invasion of NECP. Severe hypokalaemia was believed to be caused by paraneoplastic syndrome from tumor burden or by recent administration of Etoposide. Intensive potassium correction through a central venous access in maximal doses of 150 mmol/24 hours under cardiac monitoring finally raised serum potassium to 3.8 mmol/L. This safe period allowed us to perform a trephine colostomy at the left iliac fossa. The postoperative period was relatively uneventful. This first case report is presenting a rare cause of large bowel obstruction from a neuroendocrine carcinoma of prostate and highlights the importance of an early, intensive correction of electrolytes in patients with large tumor burden from NECP.

Neuroendocrine Tumor of the Ureter: A Zebra Among Horses

Primary neuroendocrine tumors of the upper urinary tract are extremely rare. We report a case of de novo small cell carcinoma of the ureter that presented masquerading as a distal ureteral stone. A 55-year-old lady presented to our clinic with 1 month history of right lower back pain and hematuria. Her history was notable for stage 1B mixed clear cell-endometroid cancer of the uterus status post radical abdominal hysterectomy with adjuvant radiotherapy, 7 years before the current episode. The patient had no evidence of recurrence. Initial noncontrast imaging suggested a 2.5 mm calculus in the distal right ureter and hydronephrosis; however, ureteroscopy revealed a large fleshy mass at the location. Histopathologic evaluation demonstrated the lesion to be primary small cell carcinoma of the ureter, without evidence of it being a derivative of the prior gynecologic malignancy. Metastatic work-up revealed high burden retroperitoneal adenopathy. The patient was started on Cisplatin-based neoadjuvant chemotherapy with plan for nephroureterectomy in the future. At 3 months follow-up, the patient was doing well with significant shrinkage of retroperitoneal adenopathy and no evidence of disease progression.

NEUROENDOCRINE RENAL CARCINOMA - THERAPEUTIC AND DIAGNOSTIC ISSUES

INTRODUCTION

Neuroendocrine renal carcinoma represents less than 1% of all primary neoplasia of the kidney. Most frequently poorly differentiated carcinoma is diagnosed in advanced stages and they have an aggressive evolution and limited survival rate. Neuroendocrine carcinomas that arise from the renal pelvis are frequently associated with squamous cell carcinoma or adenocarcinoma.

MATERIAL AND METHOD

We present the case of a female patient, known for 3 years before with an undefined retroperitoneal lymph node metastasis, being diagnosed at present with a left large cell neuroendocrine renal carcinoma, who initially had lymph node metastasis.

RESULTS

Until now, 118 cases of primary neuroendocrine renal carcinomas have been reported. A limited number of poorly differentiated neuroendocrine carcinomas have been reported.

DISCUSSION

Due to the clinical and biological findings, the aggressive evolution with early metastasis of lung and bone, the patient is included in the group of poorly differentiated carcinomas. In these cases, multimodal treatment is a gold standard. After surgical treatment and palliative chemotherapy with platinum salts, we obtained a partial remission of the disease and the control of symptoms.

CONCLUSIONS

Regarding large cell neuroendocrine carcinoma, the surgical treatment remains the treatment of choice. Chemotherapy can determine limited results, improve the quality of life and enhance the overall survival rate.

Beyond Prostate Adenocarcinoma: Expanding the Differential Diagnosis in Prostate Pathologic Conditions

Recent advances in magnetic resonance (MR) imaging of the prostate gland have dramatically improved the ability to detect and stage adenocarcinoma of the prostate, one of the most frequently diagnosed cancers in men and one of the most frequently diagnosed pathologic conditions of the prostate gland. A wide variety of nonadenocarcinoma diseases can also be seen with MR imaging, ranging from benign to malignant diseases, as well as infectious and inflammatory manifestations. Many of these diseases have distinctive imaging features that allow differentiation from prostate acinar adenocarcinoma. Early recognition of these entities produces a more accurate differential diagnosis and may enable more expeditious clinical workup. Benign neoplasms of the prostate include plexiform neurofibroma and cystadenoma, both of which demonstrate distinctive imaging features. Stromal neoplasms of uncertain malignant potential are rare tumors of uncertain malignant potential that are often difficult to distinguish at imaging from more-malignant prostate sarcomas. Other malignant neoplasms of the prostate include urothelial carcinoma, primary prostatic carcinoid, carcinosarcoma, endometrioid or ductal adenocarcinoma, and mucinous adenocarcinoma. Prostatic infections can lead to abscesses of pyogenic, tuberculous, or fungal origins. Finally, miscellaneous idiopathic disorders of the prostate include amyloidosis, exophytic benign prostatic hyperplasia, and various congenital cysts. Considerable overlap can exist in the clinical history and imaging findings associated with these prostate pathologic conditions, and biopsy is often required for ultimate confirmation of the diagnosis. However, many diagnoses, including cystadenoma, mucinous adenocarcinoma, sarcoma, and abscesses, have distinct imaging features, which can enable the informed radiologist to identify the diagnosis and recommend appropriate clinical workup and management. (©)RSNA, 2016.

Primary Small Cell Carcinoma in Urinary Bladder: A Rare Case

Small cell carcinoma of bladder, which does not have a common and accepted treatment protocol, is a rare and highly aggressive tumor. It is mostly pulmonary originated; however, it can rarely be seen in extrapulmonary sites. We presented an interesting and uncommon case, in which the transitional cell tumor was found in the transurethral resection specimen, but the small cell carcinoma was detected in the final radical cystectomy material.

Genitourinary small cell malignancies: prostate and bladder

Small cell carcinoma is an aggressive malignancy often associated with dismal prognosis due to the presence of advanced disease. Small cell malignancies, initially described in the lung (small cell carcinoma of the lung), can occur in extrapulmonary sites, such as prostate (small cell carcinoma of the prostate) and bladder (small cell carcinoma of the bladder), with similar clinicopathologic outcomes. There has been a paradigm shift in the management of small cell carcinoma of the lung from initial surgical treatment to use of chemotherapy followed by local therapies. Such treatment modalities have been applied to small cell carcinoma of the prostate and the bladder, with promise in improving patient survival. Use of platinum-based combination chemotherapy followed by surgical resection and/or radiation offers the most benefit. Further investigation at the molecular level may offer targeted therapies earlier in the course of the disease.

Primary neuroendocrine tumor (carcinoid tumor) of the testis: a case report with review of literature

BACKGROUND

The term carcinoid (Karzinoide) was coined by German pathologist Oberndorfer in 1907. Primary testicular carcinoid tumors (TCT) are rare, constituting 0.23% of all testicular tumors. In this report we describe a case of primary TCT of the testis and present the results of an extensive literature review to cover all the aspects of carcinoid tumor, including the definition, classification, origin, presentation, diagnostic evaluation, management, prognosis, and follow-up.

CASE REPORT

A 34-year-old male presented with chronic right scrotal swelling with recent onset of pain. Radical orchiectomy revealed a solid intratesticular tumor confined to the testis and epididymis, without lymphovascular invasion. Histology was consistent with neuroendocrine carcinoma. The tumor was staged as pT1 N0 M0 S2. Immunohistochemistry was positive for neuroendocrine markers. An extratesticular carcinoid tumor was ruled out. Urinary excretion of 5-hydroxyindoleacetic acid and Chromogranin A were within normal range.

CONCLUSIONS

It is important to follow serotonin levels since the elevated levels of serotonin can cause carcinoid heart disease. If metastatic lesions are not accessible for resection, a trial of octreotide therapy can be given. This case also adds to the rare reports in the literature of primary carcinoid tumors of the testis having low malignant potential. The literature review highlights new diagnostic and therapeutic interventions and stresses the importance of long-term follow-up due to evidence of delayed metastasis or recurrences and also due to emergence of new complications as a result of improved prognosis and prolonged survival.

Primary carcinoid tumor of the testis

Primary carcinoid tumors of the testis are a rare entity comprising less than 1% of all testicular neoplasms. Their presence should be considered particularly when evaluating a testicular lesion in an older male patient. Immunohistochemical studies may aid in diagnosis and radiographic evaluation is important to rule out metastatic origin. Primary carcinoid tumors of the testis are associated with an excellent prognosis; however, surveillance is important given rare reports of delayed metastases.

Primary renal large cell neuroendocrine carcinoma in a young man

Neuroendocrine tumours are usually located in the gastrointestinal or respiratory tract. A 23-year-old man was evaluated for loss of weight and a palpable left loin mass. CECT showed a large heterogeneously enhancing mass with calcification arising from the left kidney. He underwent an open radical nephrectomy. Histopathological examination revealed a large cell neuroendocrine carcinoma (LCNEC). LCNEC of the kidney is extremely rare and portends poor prognosis. It is usually a histopathological surprise and requires immunohistochemistry for confirmation.

Small cell carcinoma of the bladder

Small cell carcinoma of the urinary bladder is an extremely aggressive and rare tumor. Even though small cell carcinoma most commonly arises from the lungs there are several reports of small cell carcinoma in extrapulmonary sites. Due to its low frequency there is no well-established management for this disease. We report the case of a 61 year-old man with small cell carcinoma of the bladder who underwent radical cystectomy following neoadjuvant chemotherapy. We also reviewed the literature for the optimal treatment strategy.

Small cell carcinoma of the urinary bladder and prostate: Cytological analyses of four cases with emphasis on the usefulness of cytological examination

The occurrence of small cell carcinoma in the urinary bladder and prostate is rare. Only a few reports on the cytological features of small cell carcinoma of the urinary bladder in the urine specimen have been documented and, moreover, the urinary cytological features of prostate small cell carcinoma have been rarely reported. In this study, we analyzed the cytological features of four cases of small cell carcinoma of the urinary bladder and prostate, and discussed the usefulness of cytological examination of urine specimen for this type of tumor. This study included two urinary bladder and two prostate small cell carcinoma cases. Analyses of the cytological features of these cases revealed the following: i) the background was mostly inflammatory and necrotic material was also occasionally observed; ii) numerous tumor cells were present in two cases, whereas only a few neoplastic cells were observed in the remaining cases; iii) the neoplastic cells were small in size, had scant cytoplasm and a high nuclear/cytoplasmic ratio, and were arranged in small clusters or occasionally as single cells; iv) the tumor cell clusters showed prominent nuclear moldings; and v) the nuclei of the neoplastic cells were round to oval in shape with finely granular chromatin containing inconspicuous nucleoli. The cytological features of small cell carcinoma in the urine specimen are characteristic. Therefore, careful observation of the urine specimen may lead to a correct diagnosis of small cell carcinoma of the urinary bladder and, moreover, cytodiagnosis of prostate small cell carcinoma may also be possible.

Primary large cell neuroendocrine carcinoma of the renal pelvis: a case report

We report a case of primary large cell neuroendocrine carcinoma of the renal pelvis, diagnosed in a 79-year-old man. The abdominal computed tomography showed a solid, vegetant lesion in the left renal pelvis, conditioning marked hydronephrosis. The patient underwent radical nephroureterectomy. The histological examination showed a large cell neuroendocrine carcinoma associated with a high-grade urothelial carcinoma, with local invasion (pT3). Large cell renal neuroendocrine carcinomas are rare tumors with an aggressive course and a bad prognosis. At present, only five cases were reported in literature.

Rare testicular tumor discovered by assault: an unusual presentation of a primary testicular neuroendocrine tumor grade 2

Testicular neuroendocrine tumors (NET) or carcinoid tumors are rare neoplasms which represent 1% of all testicular tumors and can be divided into 3 subgroups: pure primary testicular NET, primary testicular NET associated with a teratoma, and NET metastases to the testis. We report an unusual presentation of a primary testicular neuroendocrine tumor in a 39-year-old male who presented after a physical altercation during a soccer game. Histology showed a diffuse infiltrating tumor with extensive involvement of the tunica albuginea and tunica vaginalis. Immunohistochemical expression of CD56, synaptophysin, and chromogranin A was strongly positive in the tumor cells. Foci of tumor cell necrosis and occasional mitotic figures as well as extensive lymph-vascular invasion were also identified. A review of the literature reveals differing opinions on the prognostic significance of primary tumor size, mitotic index, tumor necrosis, and nuclear atypia. In our patient, the increased mitotic rate (3–5 mitotic figures per 10 hpf and a Ki-67 index of 5%), foci of necrosis, and mild to moderate nuclear atypia warranted a diagnosis of neuroendocrine tumor grade 2, formerly atypical carcinoid. Long term surveillance in these patients is essential as metastasis occurs in up to 15% of cases. At the 6-month followup, the patient remains symptom free.

Metastatic primary neuroendocrine carcinoma of the genitourinary tract: A case report of an uncommon entity

Patient:

Male, 59

Final Diagnosis:

Neuroendocrine carcinoma of urinary bladder

Symptoms:

Dysuria • hematuria

Medication:

–

Clinical Procedure:

MRI • cystoscopy

Specialty:

Urology • oncology

Objective:

Rare disease

Background:

Neuroendocrine carcinomas of the genitourinary tract are rare but distinct and important entities because they are very aggressive tumors and are usually advanced or metastatic at the time of diagnosis. A high index of suspicion must be held by the pathologist viewing the specimen, as it can easily be misdiagnosed as a high grade urothelial carcinoma. Specific, proven treatment algorithms have been formulated over the years for the latter, whilst neuroendocrine carcinomas of the genitourinary tract are rare and treatment regimes have not yet been proven to show a significant improvement in survival in the majority of cases, so accurate diagnosis is important.

Case Report:

We report the case of a 59-year-old man who presented with a short history of dysuria and frank hematuria. Imaging and cystoscopy revealed a large exophytic mass in the base of the urinary bladder, which extended into the bladder neck. Metastatic deposits were already present in his liver and vertebrae. Histology revealed a neuroendocrine carcinoma.

Conclusions:

A comprehensive review of the existing literature regarding this rare but aggressive tumor is presented, including advances in classification, pathogenesis, and treatment.

A case of the large cell neuroendocrine carcinoma of the urinary bladder

Large cell neuroendocrine carcinoma (LCNEC) of the urinary bladder is very rare. Definite treatment strategy has not been established and prognosis of the disease is not clear yet. We report a case of primary LCNEC of the urinary bladder here with some review of the literature. The patient was a 84-year-old man. He underwent transurethral resection of bladder tumor (TURBT). Histological examination revealed a rosette arrangement of the tumor cells by HE staining and immunohistochemical study revealed positive CD 56, synaptophysin, and chromogranin A (LCNEC). After TURBT, he has no sign of recurrence for 8 months. We have to strictly observe the progress because LCNEC is very aggressive.

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.

Small cell carcinoma of the urinary bladder: a rare, aggressive neuroendocrine malignancy

Small cell carcinoma of the urinary bladder is a rare, often fatal, disease. Its presenting symptoms and gross morphology are similar to those of conventional urothelial carcinoma, whereas its prognosis is much poorer with frequent metastasis. Small cell carcinoma of the urinary bladder shares similar histology with its counterparts in other organs; however, its immunoreactivity to conventional neuroendocrine markers is low. Its diagnosis is thus considered permissible on morphologic grounds alone. Multimodal treatments are often employed, although no definite treatment algorithm has been established. For this extremely aggressive malignancy with an as-yet inconclusive etiology, further studies are needed to clarify its molecular pathogenesis to serve as a basis for diagnostic markers and therapeutic targets. The clinical, morphologic, immunoreactive, molecular, and therapeutic features of bladder small cell carcinoma are reviewed, including a detailed discussion on the utility of immunohistochemical markers.

A clinical review of small-cell carcinoma of the urinary bladder

Small-cell carcinoma of the urinary bladder is a rare and aggressive type of bladder cancer that has a poor prognosis. The incidence has been gradually increasing because of the aging population. Owing to its rarity there are no available treatment guidelines. Several retrospective studies and 1 prospective study have provided some insight into therapy for this disease. A multimodal approach that includes chemotherapy, local radiation therapy, and definitive surgery in resectable cases appears to be an optimal management approach.

Primary micro neuroendocrine tumor arising in a horseshoe kidney with cyst: report of a case and review of literature

Abstract

Neuroendocrine tumors are a heterogeneous group of neoplasms that arise from neuroendocrine cells. Primary renal neuroendocrine tumors are among the most unusual of all renal neoplasms, since neuroendocrine cells are not found within normal renal parenchyma. Here, a case of primary micro neuroendocrine tumor (about 4.7 mm*2 mm) arising in the horseshoe kidney with a cyst of a 45-year-old man was reported and a literature review was written.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2121156944757267

Primary carcinoid tumor of the urinary bladder with prominent subnuclear eosinophilic granules

Primary carcinoid tumor of the urinary bladder is a very rare neoplasm. We report here a case of primary carcinoid tumor of the urinary bladder with an unusual cytological feature in a 72-year-old Japanese man. A bladder polypoid mass was incidentally found by ultrasonography during the follow-up of a benign prostate hyperplasia. Histological examination of the transurethrally resected tissue revealed that the upper part of the mass was a tumor showing tubuloglandular anastomosing structures. Most of the tumor cells had peculiar subnuclear eosinophilic granules. The features of the granules were reminiscent of those observed in neuroendocrine cells of the intestine. The tumor cells were immunohistochemically positive for chromogranin A and synaptophysin. The tumor was diagnosed as carcinoid tumor of pure form of the urinary bladder. The lower part of the mass showed the findings of glandular cystitis, as its coexistence with carcinoid tumors of the bladder has often been described in previous reports.

Treatment of uncommon malignant tumours of the bladder

PURPOSE OF REVIEW

Urothelial carcinoma is the most common histological type of bladder tumours. Nevertheless, its variants and less common types represent 20% of all bladder cancers. The objective was to update the recent publications on these rare diseases and to draw conclusions for clinical management.

RECENT FINDINGS

Recent retrospective studies have been published. They refine the description of histological patterns and of immunochemistry diagnosis. Taking into account the heterogeneity of these pathologies, several groups have benefited of increased knowledge such as sarcomas and lymphomas. The need of international collaboration to study prospectively some subgroups of tumours is crucial.

SUMMARY

Rare bladder cancers have generally poor outcome and in a majority of the cases surgery, namely cystectomy remains the most important curative treatment. Specific subgroups, as lymphoma, sarcoma and dedifferentiated epithelial tumours may benefit of molecular characterization and trials with targeted drugs.

Review of small cell carcinomas of the prostate

Small cell carcinoma of the prostate is a rare neoplasm, with only a few series hitherto reported. A little less than half of the cases are associated with conventional acinar adenocarcinoma, which are usually high grade. Although consensus has not been reached, the majority of patients with small cell neuroendocrine carcinoma of the prostate have advanced disease at diagnosis and disproportionally low PSA levels compared to patients with conventional acinar adenocarcinoma. Treatment consists mainly of chemotherapy associated with surgery. Radiation therapy is reserved for selected cases. This study reviews the most up-to-date information on small cell carcinomas of the prostate.

Brain metastasis from large cell neuroendocrine carcinoma of the urinary bladder

BACKGROUND

In patients with urinary bladder cancer, brain metastases are quite rare and occur in only 1-7% of these patients. Of the urinary bladder cancers, large cell neuroendocrine carcinoma (LCNEC) is extremely rare; only 16 cases have been reported to date. In this report, a case of brain metastasis from LCNEC of the urinary bladder is described.

CASE DESCRIPTION

A 74-year-old man was admitted with confusion and left-sided hemiparesis. Head magnetic resonance imaging demonstrated a ring-enhancing lesion in the right frontal lobe. Whole body computed tomography revealed a suspicious lesion in the urinary bladder. These findings were considered consistent with metastatic brain tumor. Craniotomy and tumor removal were performed. After craniotomy, the patient underwent cystoscopy and the bladder mass was biopsied. Histological and immunohistochemical examination of both the brain tumor and bladder mass revealed LCNEC. According to these findings, the patient was diagnosed with a brain metastasis from LCNEC of the urinary bladder.

CONCLUSION

To our knowledge, this is the first report of a patient with a brain metastasis from LCNEC of the urinary bladder.