Metastatic lobular breast cancer to bladder trigone: partial response to tamoxifen

What happened, in summary

This 68-year-old woman developed persistent urge incontinence that did not improve with anticholinergic medication. Urinalysis showed an E. coli urinary tract infection, but the incontinence continued despite ciprofloxacin treatment. Ultrasound showed right hydronephrosis and thickening of the bladder wall. Cystoscopy then revealed abnormal tissue at the bladder trigone and on both sides of the bladder wall. Transurethral biopsies showed tumor cells, and immunohistochemistry was CK7-positive, estrogen receptor-positive, and progesterone receptor-positive, supporting metastatic lobular breast carcinoma rather than primary bladder cancer. Her breast cancer history dated back to 1989, when she had a right radical mastectomy and adjuvant radiotherapy for lobular breast carcinoma staged pT1N0M0. Family history included pancreatic cancer in her mother, esophageal cancer in her father, and ovarian teratoma in her daughter. Genetic testing, including BRCA1, was negative. PET-CT during the recurrence workup showed local recurrence in the right breast and confirmed the unusual metastatic site at the bladder trigone. She started tamoxifen 20 mg daily. Her urinary symptoms progressively improved within 5 months, showing that the bladder involvement was responding clinically as the endocrine therapy took effect. A follow-up PET scan showed decreased intensity in both the breast lesion and the trigone lesion. The treatment was also well tolerated, which was important because her metastatic recurrence involved an unusual urinary site rather than a typical bone or liver presentation. As of January 2012, nearly 10 months after diagnosis of recurrence, she was in clinical and partial radiologic remission, her urge incontinence had resolved, and she had no overt tamoxifen toxicities.