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Lymphoepithelioma-like carcinoma of the urinary bladder – review of the literature
Lymphoepithelioma tumours are commonly found in the nasopharynx, and histologically similar lymphoepitheliomas have been found elsewhere in the body, including the urinary bladder. Because of the rarity of lymphoepithelioma-like carcinoma (LELC) of the urinary bladder, most practitioners will be unfamiliar with its presentation, management and outcome. LELC of the urinary tract is just one of the variants of urothelial carcinoma that were added to the World Health Organization (WHO) classification in 2004, characterized by their morphological features and immunohistochemical staining characteristics, and including also the nested, microcystic, micropapillary, plasmacytoid variants. The aim of this article is to briefly outline the features of LELC based on the results of various internet searches. LELC of the urinary bladder is a rare tumour, accounting for 0.4–1.3% of all carcinomas of the urinary bladder, and occurs mainly in adults, with a reported mean age at diagnosis of 67–69 years (range 52–84 years). The majority of patients with LELC of the urinary bladder are men (75%), and fewer than 100 cases have been reported in the literature. Patients with LELC of the urinary bladder mostly present with haematuria and a definitive diagnosis is based on accurate histological interpretation. The morphological features of the tumours and the characteristic immunohistochemical staining are key to the diagnosis. Microscopically, they resemble lymphoepithelioma of nasopharynx and are Epstein–Barr virus negative. The lymphoepithelioma-like component should be >50% and microscopic examination depicts undifferentiated tumour cells in syncytial sheets with minimal cytoplasm, prominent nucleoli, numerous mitoses and lymphocytes. LELC of the urinary bladder tends to exhibit positive staining for cytokeratin (CK) 7, AE1/AE3, epithelial membrane antigen, and often p53 and B- and T-cell markers. In addition, they exhibit negative staining for CD45/leucocyte common antigen. The differential diagnosis of LELC of urinary bladder includes florid cystitis, large cell undifferentiated carcinoma, lymphoma and small cell carcinoma. These tumours are usually muscle-invasive and often coexist with transitional cell carcinoma and carcinoma in situ. Chronic inflammation may obscure the tumour and cystectomy is usually employed as a treatment method in view of the fact that the tumour may be multifocal with synchronous urothelial carcinoma. There is no consensus on the optimum treatment in view of the rarity of the disease. Nevertheless, there is evidence to suggest that patients with pure or predominant LELC of the urinary bladder should undergo transurethral resection with or without adjuvant cisplatin-based systemic chemotherapy and focal LELC should be treated by radical cystectomy with adjuvant cisplatin-based systemic chemotherapy. After bladder-preserving treatment, the patient should undergo regular follow-up cystoscopies.