Myeloid Sarcoma Presenting as Low Back Pain in the Pediatric Emergency Department.

BACKGROUND: Low back pain is a common symptom in the pediatric population; approximately half of all children present with at least one episode of low back pain. The majority of cases are due to nonspecific causes such as musculoskeletal trauma with spontaneous regression. On some occasions, however, life-threatening diseases have to be considered.

CASE REPORT: A 15-year-old girl presented to the Pediatric Emergency Department for a history of continuous 2-day duration of low back pain and transient paresthesia of the right gluteal area. Low back pain was diagnosed and nonsteroidal anti-inflammatory treatment combined with rest were prescribed. After 7 days, worsening of the clinical conditions was observed with bilateral gluteus paresthesia. A corset was recommended, and magnetic resonance imaging (MRI) and rheumatological evaluation were prescribed on an outpatient basis. After 5 days she was hospitalized due to urinary incontinence and persistence of pain. Blood tests revealed neutrophil leukocytosis associated with mild anemia, thrombocytopenia, hyperuricemia, and increased lactate dehydrogenase. MRI examination of the spine demonstrated a mass involving the sacral canal and the presacral region, extending through the sacral foramina, along the nerve roots. Similar tissue was found at multiple levels in the spine and in the right orbit. Bone marrow aspiration and biopsy highlighted the presence of myeloid blasts and myeloid dysplasia, consequently, myeloid sarcoma was diagnosed. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Our case demonstrates the importance of prompt identification of diagnostic "red flags" in childhood low back pain, indicating the need for diagnostic investigations such as MRI and blood tests.