Breast cancer with an unusual leukemia-like presentation: case report and literature review.

Breast cancer is the most common cancer in women in the world and the second-most common cancer in women in Taiwan. However, breast cancer with plentiful leukemia blast-like cells circulating in the peripheral blood is very rare. A 48-year-old woman with breast cancer and leukemia-like manifestations was admitted in August, 2006. Special staining and immunophenotyping studies to determine the origin of her peripheral blast cells confirmed that they were from her breast carcinoma. Carcinocythemia (carcinoma cell leukemia) was diagnosed and then systemic chemotherapy and hormone therapy were given. Nevertheless, she expired 9 months after carcinocythemia presentation. The differential diagnosis of this condition, which is complicated by chemotherapy or radiotherapy for solid tumors, is very important. Patients with carcinocythemia have poor prognosis and survival.