Spontaneous remission of acute lymphoblastic leukemia: A series of nine cases and a review of literature.

Aims: To report a series of acute lymphoblastic leukemia (ALL) cases with spontaneous remission and provide presenting clinical and pathologic information and details of clinical course to raise awareness among oncologists and patients.

Methods: We identified and analyzed nine patients with ALL and spontaneous remission. Review of literature reveals an additional nine previously reported cases with similar clinical course.

Results: All of these patients, ranging in age from 2 to 12 years of age, presented with inciting signs and symptoms of viral or bacterial infection. All of the patients showed varying percentages of lymphoblasts (.2% to 90%) in diagnostic bone marrow biopsy. All B-ALL cases shared a similar blast phenotype on flow cytometry with coexpression of CD19, CD10 and TdT and variable CD20 expression. All nine patients achieved spontaneous remission of their leukemia as confirmed by flow cytometry and/or bone marrow biopsy without chemotherapeutic intervention. Time to remission from presentation ranged from 1 to 8 weeks. After remission, all patients redeveloped ALL, and time from remission to reemergence ranged from 2 to 24 weeks.

Conclusion: Our series of cases and cases identified in literature show that ALL diagnosed with modern methods of flow cytometry and molecular analysis will recur within weeks to months from disappearance, usually with cytopenias, which provides a template for oncologic follow-up and testing in these patients.