A rare bladder cancer--small cell carcinoma: review and update

Abstract

Small cell carcinoma of the bladder (SCCB) is rare, highly aggressive and diagnosed mainly at advanced stages. Hematuria is the main symptom of this malignancy. The origin of the disease is unknown; however the multipotent stem cell theory applies best to this case. Histology and immunohistochemistry shows a tumour which is indistinguishable from small cell lung carcinoma (SCLC). Coexistence of SCCB with other types of carcinoma is common. The staging system used is the TNM-staging of bladder transitional cell carcinoma. The treatment is extrapolated from that of SCLC. However, many patients with SCCB undergo radical resection which is rarely performed in SCLC. Patients with surgically resectable disease (< or = cT1-4aN0M0) should be managed with multimodal therapy associating chemotherapy, surgery and/or radiotherapy. Neoadjuvant chemotherapy using four chemotherapy cycles followed by radical cystectomy is the most effective therapeutic sequence. Patients with unresectable disease (> or = cT4bN+M+) should be managed with palliative chemotherapy based on neuroendocrine type regimens comprising a platinum drug (cisplatin in fit patients). The prognosis of the disease is poor mainly in the case of pure small cell carcinoma. Other research programs are needed to improve the outcome of SCCB.

Figure 1

Pathology of small cell carcinoma of the bladder [31,43]. A. Hematoxylin and eosin (H and E) staining of the biopsy specimen, low-power view: Urothelial mucosa unfiltered by poorly differentiated carcinomatous proliferation comprised sheets of monomorphic cells. B. Hematoxylin and eosin (H and E) staining of the biopsy specimen, high-power view (×20): Proliferation comprised small cells with hyperchromatic nuclei infiltrating the muscle. C. Hematoxylin and eosin (H and E) staining: High-power view (×40) of a transurethral resection of small cell carcinoma, showing typical scant cytoplasm, increased mitotic index, spindling, and prominent nuclear moulding. D. Immunostaining: NSE-antibody-positive bladder tumor cells

Figure 2

Bladder small cell carcinoma imaging [31]. A. Computed tomography scan of the pelvis shows a heavy tumor at the right bladder wall with intraluminal and extravesical extension (arrows). B. Computed tomography scan of the abdomen shows a multinodular liver disease from bladder small cell carcinoma (arrows).

Figure 3

Deregulated signaling pathways and targeted therapy which should be evaluated in the future in SCCB in analogy to SCLC. Abbreviations: EGFR, Epidermal Growth Factor Receptor; VEGFR, Vascular Endothelial Growth Factor R; FGFR: Fibroblast Growth Factor Receptor; PDGFR, Platelet Derived Growth Factor Receptor; mTOR: mammalian Target of Rapamycin.