Abstract
Acute lymphoid leukemia (ALL) is a malignant proliferation of abnormal lymphoid precursors in the bone marrow. It is the most common acute leukemia in childhood, accounting for only 20% of acute leukemia in adults. The clinical presentation is heterogeneous including pallor, fatigue and weakness. Diagnosis is performed through myelogram, bone marrow biopsy and immunophenotyping. Chemotherapy and, in some cases, bone marrow transplantation (BMT) are used to treat the disease. However, the efficacy of treatment in adult patients is still below expected and therapeutic innovations have not increased disease-free survival. In addition, about 20% of patients have relapse, usually generalized, of the disease. This article aims to report the case of a patient previously treated for ALL B presenting localized medullar relapse or in situ leukemia.