Most urinary bladder tumors are predominantly urothelial in origin and nonurothelial malignancies such as small cell, squamous cell or adenocarcinomas are relatively rare. In males, while adenocarcinomas arising from the bladder urothelium may sometimes be encountered, it is more common from either direct extension from the colon or prostate or from a distant metastasis. Primary adenocarcinoma of the urinary bladder is a rare malignancy and accounts for less than 2% of all primary bladder malignancies. We herein present a case with extensive literature review focusing on the diagnosis and treatment of the disease.

We report a case of 57-year-old bedridden man due to spinal cord injury who suffered from recurrent urinary tract infection and presented with intermittent left flank pain. Abdominal CT showed bilateral renal stones and left upper ureteral stone complicated with left hydronephrosis. Left percutaneous nephrostomy tube was inserted for decompression of hydronephrosis and we scheduled him for ureteroscopy stone lithotripsy. During cystoscopy inspection, a huge bladder diverticulum with much papillomatous, villous like lesions resides within along with thick gelatinous-like mucous urine. We shifted the procedure to transurethral resection of bladder tumor instead in suspicion of bladder urothelial carcinoma.

Final pathology report with immunohistochemistry(IHC) revealed high grade adenocarcinoma, Abdominal MRI was arranged and was unremarkable for any gastrointestinal, colorectal lesions confirming the disease's primary nature.

Primary adenocarcinoma of the urinary bladder is a rare malignancy. Its diagnosis poses great challenges but methods such as IHC and tumor markers may assist with exclusion of metastasis. Treatment is inconclusive and needs further research but radical cystectomy is the accepted treatment of choice for muscle invasive cases while chemotherapy may provide benefit in advanced cases with regimens for colorectal or ovarian cancers.