NEJM Case 13-2013: A 6-Year-Old Girl with Bone and Joint Pain and Abdominal Distension

Background: B-Cell Acute Lymphoblastic Leukemia/Lymphoma (B-ALL) is the most common childhood malignancy. B-ALL has good prognostic outcomes when diagnosed in its early stages, with a 5 year overall survival rate > 85%. Case: A 6-year-old female initially presented to her pediatrician's office with bone pain following a fall and was repeatedly evaluated by her orthopedist and rheumatologist for recurrent limb pain over a year. She eventually developed a high intermittent fever of 39.8C, abdominal distention/discoloration, and periorbital erythema/edema. On admission at Massachusetts General Hospital, her physical exam findings were consistent with the pre-admission evaluation and labs were notable for normal WBC and platelet counts. CT and PET studies showed lymphadenopathy, multiple lytic lesions, and a large abdominal mass with increased uptake. Examination of a biopsy specimen from the abdominal-pelvic mass showed a monotonous population of primitive cells. Immunohistochemical studies of these cells showed coexpression of terminal deoxynucleotidyl transferase (TdT) and CD10, as well as positivity for the B-cell marker PAX5, consistent with B lymphoblasts. The patient was diagnosed with B-ALL one year after her first bone pain episode. After treatment with a 3-drug induction and two bone marrow transplants, she died 20 months after her diagnosis. Conclusion: This case demonstrates the varied presentation of B-ALL that requires physicians to maintain a high index of suspicion. Despite its good prognosis, the presentation with intra- and extramedullary involvement and normal hematologic values can be a challenge to physicians evaluating young patients.