Purpose or Case Report: Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy. Children with ALL are at risk for developing acute pancreatitis (AP) during treatment, most commonly related to asparaginase. According to the American College of Radiology guidelines, ultrasound (US) should be the first line imaging modality in the diagnosis of AP. However, AP in children with ALL is thought to be due to direct pancreatic injury rather than ductal obstruction, and thus US may not be the optimal imaging modality for this diagnosis.
Methods & Materials: This retrospective study was approved by the institutional review board. Protocol databases were searched for ALL patients who were diagnosed with AP during therapy, according to Common Terminology Criteria for Adverse Events (CTAE) version 3. This list was cross-referenced with the diagnostic imaging database to identify patients who had undergone abdominal US or CT within 10 days of AP diagnosis. Chemotherapy dosing, amylase/lipase levels, clinical symptoms, and dates of imaging studies were recorded. All CT and US studies were overread by a radiology trainee blinded to the original imaging report, for findings of AP according to the CT Severity Index (CTSI) and the Revised Atlanta Classification. Discrepancies in the diagnosis of AP were adjudicated by a pediatric radiologist.
Results: 69 patients, ranging from 2-21 years, experienced 88 episodes of AP (between 2008-2018) and underwent 98 US and 44 CT exams. 72/88 (82%) events occurred within 30 days of asparaginase administration. 69 events (69/88, 78%) were diagnosed clinically by the presence of abdominal pain and amylase/lipase levels greater than 3 times the upper limit of normal. No imaging was obtained in 18 (20%) of events. The pancreas was completely obscured in 12/98 (12%) of US exams and was never visualized in entirety by US. The overall sensitivity for the detection of AP was 47% by US. Although obtained less frequently, CT detected AP in all but one case (98% sensitivity). CTAE Grade 4 events had the highest CTSI scores, highest percentage of necrotizing pancreatitis, and highest US sensitivity (83%).


Conclusions: Most cases of AP in children being treated for ALL can be diagnosed with clinical history and labs. When imaging is used, US is much less sensitive in detecting AP than CT, except in the most severe cases (CTAE Grade 4). Imaging to diagnose AP in this patient population should be limited to clinically equivocal cases.