Neuroendocrine Tumors of the Urinary Bladder According to the 2016 World Health Organization Classification: Molecular and Clinical Characteristics

Abstract

Neuroendocrine neoplasms of the urinary bladder are a rare type of tumor that account for a small percentage of urinary bladder neoplasms. These tumors of the urinary bladder range from well-differentiated neuroendocrine neoplasms (carcinoids) to the more aggressive subtypes such as small cell carcinoma. Despite the rarity of the neuroendocrine tumors of the bladder, there has been substantial investigation into the underlying genomic, molecular, and the cellular alterations within this group of neoplasms. Accordingly, these findings are increasingly incorporated into the understanding of clinical aspects of these neoplasms. In this review, we provide an overview of recent literature related to the 2016 World Health Organization Classification of Neuroendocrine Tumors of the Urinary Bladder. Particular emphasis is placed on molecular alterations and recently described gene expression. The neuroendocrine tumors of the urinary bladder are subdivided into four subtypes. Similar to their pulmonary and other extrapulmonary site counterparts, these have different degrees of neuroendocrine differentiation and morphological features. The clinical aspects of four subtypes of neuroendocrine tumor are discussed with emphasis of the most recent developments in diagnosis, treatment, and prognosis. An understanding of molecular basis of neuroendocrine tumors will provide a base of knowledge for future investigations into this group of unusual bladder neoplasms.

The Colorful Palette of Neuroendocrine Neoplasms in the Genitourinary Tract

“…According to other theories, the tumor originates from metaplastic bladder urothelium or from transformed neuroendocrine cells, especially in the region of the trigone (12). The exact cellular origin of bladder NET is still unknown; however, it has been postulated that NETs may arise from NE cells of different kind of reactive lesions (36). Microscopic features are similar to NETs located in other organs.…”

“…In addition, prostate-specific acid phosphatase (PAP) expression was detected. No other prostate marker positivity can be detected (36). Due to the lack of long-term follow-up data, the prognosis cannot be exactly estimated.…”

“…Large cell neuroendocrine tumor (LCNEC) of the bladder is an extremely rare form of cancer with fewer than 25 reported cases (61). The disease mainly develops in elderly male patients (36). Histologically, LCNEC is identical to large cell carcinoma of the lungs.…”

Acute Decompensation of Hypertensive Heart Disease in Patient With Malignant Urinary Bladder Paraganglioma: Stages of Diagnostics and Treatment

“…Определяющей в развитии сердечной недостаточности у нашего пациента была выраженная диастолическая дисфункция, Второй диагностической проблемой являлась верификация диагноза параганглиомы. Параганглиома мочевого пузыря является очень редкой опухолью, составляя менее 0,05-0,06% опухолей мочевого пузыря и 1-6% всех вненадпочечниковых феохромоцитом [6,7]. По данным европейского общества гипертензии, доложенным на конгрессе ESC 2017 г., все феохромоцитомы ответственны лишь за 0,5% случаев АГ, т.е.…”

Rare Occurrence of a Poorly Differentiated Neuroendocrine Tumor of the Bladder

“…They may present with asymptomatic hematuria at an advanced pathologic stage and have a poor prognosis. Although they only comprise 0.35–1% of all bladder tumors, they have been extensively studied for gene expression and molecular basis [1, 2]. These tumors can be divided into carcinoid, neuroendocrine carcinoma, or mixed histology.…”