Bladder's Blind Spot: A Rare Case of Non-bilharzial Diverticular Squamous Cell Carcinoma Treated With Partial Cystectomy.

Squamous cell carcinoma (SCC) is an uncommon malignancy found within the bladder diverticulum. Early extravesical invasion is more likely to occur in diverticula when there is no muscle layer present. The gold standard for bladder SCC is radical cystectomy (RC), although in individuals with poor performance status, it might not be feasible. This case report describes a rare example of primary intra-diverticular SCC that was treated well with adjuvant radiation therapy and partial cystectomy (PC). A 68-year-old man was experiencing increasing frequency of urination and painless hematuria for three months. In a bladder diverticulum, moderately differentiated SCC (pT3aN0M0) was confirmed by imaging and histological examination. RC was not a viable alternative due to the poor performance condition. The patient received adjuvant radiation for microscopic extravesical extension after undergoing a PC and bilateral pelvic lymphadenectomy. During a five-year follow-up, routine cystoscopy and yearly imaging revealed that he was symptom-free and had not experienced any metastases or recurrence. This scenario shows that for certain individuals who are not suitable candidates for RC, PC combined with lymphadenectomy and adjuvant radiation therapy is a good substitute for localized bladder diverticular SCC. Due to SCC's aggressive nature and high recurrence rates, long-term surveillance, aggressive management, and early identification are crucial for bladder-preserving strategies.