A case of advanced breast cancer with Gitelman syndrome.

Gitelman syndrome (GS) is a rare, mostly autosomal recessive disease this is a salt-losing tubulopathy caused by mutation of genes encoding sodium chloride (NCCT) and magnesium transporters in the thiazide-sensitive segments of the distal nephron. We encountered a 45-year-old female who has suffered from whole-body weakness because of hypokalemia for 8 years and diagnosed with Gitelman syndrome clinically. She visited the hospital with a complaint of an unrelieved hard mass of the left breast. The tumor was diagnosed as human epidermal growth factor receptor 2 (HER2)-positive breast cancer. We herein report this first case of a breast cancer patient with Gitelman syndrome who developed other neoplasms including colon polyp, adrenal adenoma, an ovarian cyst, and multiple uterine fibroids and provide a review of the pertinent literature.