A novel treatment approach prolonging survival in an uncommon metastatic primary bladder adenocarcinoma.

Primary bladder adenocarcinoma (PBA) is an epithelial malignancy with pure glandular differentiation, without evidence of typical urothelial (transitional cell) carcinoma. PBA is rare, accounting for 0.5%-2% of all malignant bladder neoplasms, and it is seen more frequently in men than in women and is commonly diagnosed in the sixth decade of life.¹⁻³ Clinical presentation includes hematuria and symptoms of bladder irritation.² PBA is common in schistosomiasis-endemic regions and among patients with congenital bladder exstrophy (ectopia vesicae); it mostly arises in the trigone and posterior bladder wall.⁴ In contrast, urachal adenocarcinomas arise within urachal remnants (residual tissues from the embryonic allantoic stalk connecting the umbilicus and bladder), close to the dome and anterior wall of the bladder. Morphologically, PBA is classifed into enteric and nonenteric types, which includes mucinous, signetring cell variant, clear-cell type, hepatoid, and mixed forms.² Currently, there is no standard of care in the management of PBA. We present the case of a patient with metastatic PBA with intestinal differentiation and wild-type KRAS, who was treated with colorectal cancer regimens.