Obesity as the initial manifestation of central nervous system relapse of acute lymphoblastic leukemia: case report and literature review.

A 6-year-old boy with acute lymphoblastic leukemia in remission experienced hyperphagia, obesity, and emotional disorders. Cytomorphologic examination of cerebral spinal fluid (CSF) and cranial MRI did not help in differentiating between central nervous system leukemia (CNSL) and other CNS diseases including tuberculosis in this boy. Flow cytometric CSF analysis on repeated lumber puncture detected lymphoblasts, while microscopic CSF examination did not definitively show relapse disease. The diagnosis of CNSL was thus made and confirmed by the response to leukemia treatment. Obesity can be the first manifestation of CNSL and the diagnosis can be challenging. A combination of CSF cytomorphology, CSF flow cytometry, and cranial MRI can be useful in the diagnosis of the disease. Two mechanisms of CNSL-related obesity are discussed based on the literature review.