Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.
Department of Urology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.
Hum Pathol. 2018 Sep;79:57-65. doi: 10.1016/j.humpath.2018.05.005. Epub 2018 May 12.
Small cell carcinoma (SmCC) of the bladder is a rare disease. We retrospectively studied a large series of bladder SmCC from a single institution. The patients included 69 men and 12 women with a mean age of 68 years. Most bladder SmCCs were presented at advanced stage, with tumors invading the muscularis propria and beyond (n = 77). SmCC was pure in 27 cases and mixed with other histologic types in 54 cases, including urothelial carcinoma (UC) (n = 32), UC in situ (n = 26), glandular (n = 14), micropapillary (n = 4), sarcomatoid (n = 4), squamous (n = 3), and plasmacytoid (n = 1) features. Most SmCCs expressed neuroendocrine markers synaptophysin (41/56), chromogranin (26/55), and CD56 (39/41); however, they did not express UC luminal markers CK20 (0/17), GATA3 (1/30), and uroplakin II (1/22). Some SmCCs showed focal expression of CK5/6 (9/25), a marker for the basal molecular subtype. Furthermore, expression of the retinoblastoma 1 (RB1) gene protein was lost in most of the bladder SmCCs (2/23). The patients' survival was significantly associated with cancer stage but did not show a significant difference between mixed and pure SmCCs. Compared with conventional UC at similar stages, SmCC had a worse prognosis only when patients developed metastatic diseases. In conclusion, bladder SmCC is an aggressive disease that is frequently present at an advanced stage. A fraction of SmCCs show a basal molecular subtype, which may underlie its good response to chemotherapy. Inactivation of the RB1 gene may be implicated in the oncogenesis of bladder SmCC.
膀胱小细胞癌（SmCC）是一种罕见的疾病。我们对来自单一机构的大量膀胱 SmCC 病例进行了回顾性研究。这些患者包括 69 名男性和 12 名女性，平均年龄为 68 岁。大多数膀胱 SmCC 处于晚期，肿瘤侵犯肌层及以外（n=77）。27 例为纯 SmCC，54 例为混合性组织学类型，包括尿路上皮癌（UC）（n=32）、原位 UC（n=26）、腺癌（n=14）、微乳头状（n=4）、肉瘤样（n=4）、鳞状（n=3）和浆细胞样（n=1）特征。大多数 SmCC 表达神经内分泌标志物突触素（41/56）、嗜铬粒蛋白（26/55）和 CD56（39/41）；然而，它们不表达 UC 腔面标志物 CK20（0/17）、GATA3（1/30）和 uroplakin II（1/22）。一些 SmCC 表现出 CK5/6 的局灶性表达（9/25），这是基底分子亚型的标志物。此外，大多数膀胱 SmCC 的视网膜母细胞瘤 1（RB1）基因蛋白表达丢失（2/23）。患者的生存与癌症分期显著相关，但混合性和纯 SmCC 之间无显著差异。与相似分期的常规 UC 相比，只有当患者发生转移性疾病时，SmCC 才会导致更差的预后。总之，膀胱 SmCC 是一种侵袭性疾病，常处于晚期。有一部分 SmCC 表现出基底分子亚型，这可能是其对化疗反应良好的基础。RB1 基因失活可能与膀胱 SmCC 的发生有关。
