Occult breast cancer with EDTA-dependent pseudothrombocytopenia -a case report-.

A case of occult breast cancer with pseudothrombocytopenia (PTCP) is reported. A 50-year-old woman was consulted with a left axillary tumor. Ductal carcinoma was found by the core needle biopsy, and no primary lesion was detected. Her preoperative platelet count, obtained from an ethylene diamine tetraacetic acid (EDTA) sampling bottle, was 3.1 x 10(4) per mL, but she had no history of bleeding problems. A heparinized blood sample showed a normal platelet count of 390 x 10(4) per mL. These findings suggested a diagnosis of occult breast cancer with EDTA-dependent PTCP, and level II axillary lymph node dissection was performed. She received adjuvant chemotherapy and radiotherapy, but she died 2 years and 5 months after the surgery because of lung and brain metastases. Awareness of the phenomenon and knowledge of the underlying physiological principles will enable surgeons to manage patients with EDTA-dependent PTCP appropriately.