Transdifferentiation of Small Cell Carcinoma of the Urinary Bladder from Urothelial Carcinoma after Transurethral Resection of a Bladder Tumor, Intravesical Bacillus Calmette-Guerin Instillation, and Chemotherapy: A Case Report

Abstract

A 73-year-old male underwent transurethral resection of a bladder tumor in August 2010 and April 2011. Pathological examination revealed urothelial carcinoma. After the surgery, chemotherapy and intravesical Bacillus Calmette-Guerin instillation were performed. In September 2014, he once again underwent transurethral resection of the bladder tumor for recurrence, and was again diagnosed with urothelial carcinoma, pT2, by pathological examination. After neoadjuvant chemotherapy, radical cystectomy for tumor recurrence was performed. Pathological examination at this time revealed small cell carcinoma, pT3N0. It is rare for urothelial carcinoma to change to small cell carcinoma, and the mechanism and cause of this change are still unknown. In this case report, we discuss what causes small cell carcinoma of the urinary bladder and review the literature regarding its origin.

A genetically defined disease model reveals that urothelial cells can initiate divergent bladder cancer phenotypes

“…This indicates that cells from 1 cancer phenotype can give rise to another phenotype, presumably through processes involving transdifferentiation. This is concordant with prior reports of therapy-induced transdifferentiation (52). Our model thus provides a resource for the investigation of this clinically impactful plasticity.…”

Recurrent urethral tumor with neuroendocrine differentiation in a female patient after radical cystectomy for bladder cancer

“…It is more common in male than female patients, with a ratio of 3.3:1.0 10 . Most reported cases are mixed variants containing elements, such as UC, squamous cell carcinoma, and adenocarcinoma, as shown in our patient 5 . Both a recurrent bladder tumor containing SmCC and a primary SmCC of the urethra is extremely rare in female patients.…”

“…1 Moreover, recurrent bladder tumors with neuroendocrine differentiation are extremely rare with only five cases reported since 2000. [2][3][4][5][6] Herein, we describe the first case of simultaneous occurrence of both rare conditions; a recurrent urethral tumor showing neuroendocrine differentiation in a female patient after RC for conventional UC.…”

The natural course of bacillus Calmette-Guérin induced bladder lesions: A long-term follow-up study and systematic review

“…2 ). As a result, a total of 15 cases with detailed cystoscopic and pathologic descriptions from 14 studies were identified [ [8] , [9] , [10] , 16 , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] ]. The clinical characteristics of the selected cases were summarized in Supplementary Table 1 .…”