Background: Bladder cancer is usually of urothelial origin. Locoregional metastases to the bladder may occur. Distant metastases to the bladder are rare.
Case presentation: We present a woman in her eighties diagnosed with breast cancer (infiltrating lobular carcinoma). Three years after her treatment (surgery and radiotherapy), she was referred to the department of urology with macroscopic haematuria and night sweats. She was diagnosed with kidney stones based on the results from CT scans, urine cytology and cystoscopy. A few months after the urological evaluation, the patient had increasing MUC1 (CA 15 - 3) levels. Radiological and gynaecological examination did not reveal metastases. Due to recurrent haematuria, the urological workup with cystoscopy and CT was repeated, which revealed bladder pathology. Histology from these changes showed metastases from breast cancer.
Interpretation: Distant metastases to the bladder may be hard to detect. In this case, concurrent kidney stones made the diagnosis even more challenging.