Bone Pain as a Clinical Presentation of Acute Lymphoblastic Leukemia

Introduction: Acute lymphoblastic leukemia (ALL) is the most common malignancy in children, accounting for approximately 1/3 of pediatric cancers. Treatment of ALL has progressed extensively over the years, and approximately 85% of pediatric ALL cases achieve remission. Many factors are used in determining the treatment for individuals, including central nervous system infiltration, chromosomal abnormalities, and various mutations. Most patients present with systemic signs and symptoms that lead the pediatrician towards the diagnosis of ALL, but some present with the chief complaint of bone pain. Case Information: Case 1: A 5-year-old female presented to an urgent care clinic complaining of low back pain for the past 2 weeks. Initially, an X-ray was performed which showed anterolisthesis and diminished vertebral height. Following the X-ray, she was evaluated and found to have additional symptoms including a low-grade fever, headache, nasal discharge, and cough. Labs drawn revealed pancytopenia and an MRI scan revealed an infiltrative process of the L3 vertebral body. Bone marrow biopsy confirmed the diagnosis of B-cell ALL. The patient was started on standard risk therapy, but had positive minimal residual disease (MRD) at day 29 of treatment. Patient was then placed on the high risk treatment protocol. Patient is now in maintenance therapy. Case 2: A 4-year-old female presented to an emergency department with left upper arm pain and a recent episode of strep throat. Exam showed some lymphadenopathy and painful range of motion testing in the left arm. X-ray was unremarkable. Labs showed the patient to be anemic. White blood cell numbers were within normal range, however the differential count identified abnormal lymphocytes to be present. Bone marrow biopsy confirmed diagnosis of B-cell ALL. Patient was started on standard risk therapy, achieved MRD negative remission, and is currently in maintenance therapy. Conclusions: This case study reviews 2 cases out of many that presented with similar complaints of bone pain. Often children experience minor trauma, such as falling out of a chair, which may cause pain. Pediatricians may see many such cases, but sometimes the bone pain is a manifestation of something more serious. Lack of awareness can lead to a delay in diagnosis of ALL. Therefore, ALL should always be considered when evaluating a child for bone pain.