Rare histological subtypes of bladder cancer in clinical practice: a case series

Non-urothelial tumors account for less than 5% of all bladder malignant neoplasms. The most common non-urothelial tumor is squamous cell carcinoma, often found in the Middle East (about 30% of all cases of bladder cancer BC) due to the spread of schistosomiasis. The glandular type is the second most common non-urothelial morphological variant; it includes 5 tumor subtypes (intestinal, mucinous, signet ring cell, mixed, and adenocarcinoma not otherwise specified). The neuroendocrine variant is divided into 4 subgroups (small cell, large cell, highly differentiated, and paragangliomas), of which small cell is the most common, though still rare, and accounts for only about 1% of all BCs. The article presents the clinical cases of three rare BC subtypes: squamous cell, glandular, and neuroendocrine. In the first clinical case, a radical cure of a patient with signet ring cell BC was described: at the first stage, the bladder, prostate, and vesicles were removed with a cystoplasty using a small intestine segment according to the Bricker technique with an extended pelvic lymph node dissection; the second stage included 8 courses of adjuvant drug treatment according to the XELOX regimen. In the second clinical case, the treatment of the metastatic neuroendocrine BC was described using the following regimens: EP (etoposide + cisplatin), carboplatin + irinotecan, GemOx (gemcitabine + oxaliplatin). The third clinical case described a patient with bladder squamous cell carcinoma. The stage I treatment was based on the GC regimen; at stage II, the bladder, prostate, and vesicles were removed with intestinal orthotopic cystoplasty and extended lymph node dissection; due to progression revealed during the follow-up examination, the patient received another GC course. Although non-urothelial BCs are very rare, studies are currently being conducted on the effectiveness of immunotherapy and targeted therapy in treating this cohort of patients.