Lower leukocytes at initial diagnosis may predict poor outcome of very late relapse of acute lymphoblastic leukemia

We have reported a rare case of acute lymphoblastic leukemia (ALL) recurring 19 years after the first presentation. Since 1984, 36 relapse cases 10 years or more after the first diagnosis have been reported. All cases were childhood ALL with a low to standard risk. Twenty-six attained CR2, and 18 of them remained in sustained CR2. The sustained CR2 ratio was 80% without transplantation. Sustained CR2 ratio was significantly lower in patients with lower leukocytes (<10 × 109 l−1) at initial presentation. A very late relapse of ALL remains chemosensitive, and its prognosis is not unfavorable.