A case of lymphoepithelioma-like carcinoma of the urinary bladder

Abstract

Background : Lymphoepithelioma-like carcinoma of the urinary bladder is a rare invasive urothelial carcinoma subtype that resembles lymphoepithelial carcinoma arising in the nasopharynx, and accounts for ＜1％ of all bladder cancers. Herein, we report a case of this subtype of cancer of the urinary bladder with detailed cytological findings.

Case : An 84-year-old woman presented with gross hematuria. Cystoscopy and MRI showed a 30-mm nodular (broad base) tumor in the bladder trigone area. Urinary cytology revealed large atypical cells with an inflammatory background comprising neutrophils and mature lymphocytes. Atypical cells appeared as small clusters with unclear cell borders that adhered to mature lymphocytes and showed an elevated N/C ratio, mildly irregularly-shaped and enlarged nuclei with fine granular chromatin and a few distinct nucleoli, and pale cytoplasm. Histologically, carcinoma cells proliferated in a syncytia-like manner with indistinct cell boundaries, in a stroma containing numerous neutrophils, mature lymphocytes, and plasma cells.

Immunohistochemically, the carcinoma cells showed positive staining for CK (AE1/AE3) and GATA3. In-situ hybridization analysis revealed that the carcinoma cells were EBER-negative. Based on the findings, the tumor was diagnosed as a lymphoepithelioma-like invasive urothelial carcinoma.

Conclusion : Detection of small clusters of carcinoma cells with pale cytoplasm containing mildly irregularly-shaped and enlarged nuclei with fine granular chromatin and a few distinct nucleoli may help in distinguishing between the lymphoepithelioma-like and conventional subtypes of urinary bladder cancer. The presence of a lymphoepithelioma-like carcinoma component portends a better response to chemotherapy and better prognosis than in the conventional-type of urinary bladder cancer.