RESUMO
INTRODUCTION: Osteoporosis in children is rare and usually secondary to an underlying disease process whose diagnosis may be difficult to detect. Etiological factors responsible for osteoporosis secondary to chronic illness include immobility, pubertal delay and other hormonal disturbances. Rarely, it can be a manifestation of acute lymphoblastic leukemia. Most of the reported bone fracture incidences associated with acute lymphoblastic leukemia occur during the course of the chemotherapy, not at the point of the first symptoms of leukemic disease, as happened with the case presented here. CASE PRESENTATION: A 7-year-old Asian Balinese boy presented with back pain. His anteroposterior pelvic radiograph showed osteoporotic bone. A bone age study revealed growth failure of his metacarpals, phalanges and sesamoid. His total bone mass density was 97% age-match. However, a peripheral blood smear showed normochromic anemia with thrombocytopenia. Immunophenotyping of his peripheral blood revealed no dominant markers, but a bone marrow aspiration confirmed a diagnosis of acute lymphoblastic leukemia. CONCLUSIONS: Osteoporosis was the only manifestation of the child's underlying acute lymphoblastic leukemia. Leukemia was diagnosed when his bone marrow was found to contain more than 25% blasts. Because of leucopenia, the immunophenotype failed to reveal a dominant marker in this case, thus we were unable to classify the acute lymphoblastic leukemia.
