The Spectrum of Paediatric Abdominal Masses: Correlation of Imaging Findings and Histology.

Abstract

Background Pediatric abdominal masses are a common source of morbidity and mortality more-so in Africa where resources are limited and therefore patients tend to present late with advanced disease. The aim of this study was to establish the local imaging spectrum and histological correlation of abdominal masses in children at Kenyatta national hospital. Objective To establish the local imaging spectrum and a histological correlation of abdominal masses in children at Kenyatta National hospital. Materials and methods A prospective cross-sectional study was done at Kenyatta national hospital, radiology department between September 2018 to March 2019. Out of the 140 children who were referred for imaging with suspicion of an abdominal mass, 123 fulfilled the inclusion criteria and were therefore enrolled in the study. Ultrasound was done by the primary investigator under the supervision of a consultant radiologist. CT or MRI were performed by experienced radiographers and reported by the principal investigator under the supervision of an experienced radiologist. Standardized reporting protocol was used in all the cases. Description of the organ involved, size, texture, vascularity, effect of the mass on adjacent structures and imaging diagnosis was then recorded on a data sheet. Of the 123, only 78 patients had a histological diagnosis which was also recorded. Data was analyzed using SPSS version 23, Microsoft Access and Excel. It was then represented on tables and graphs. Imaging diagnosis and histological diagnosis were compared. Results In this study, 123 patients age range of 4 days -17 years, mean of 5.12 (SD=3.6) and a male to female ratio is ratio was 1:1.1 were analyzed. Imaging which included Ultrasound (94%), CT (53.7%) and MRI (1.6%) was done at the radiology. Prevalence of abdominal

masses in the sampled population was 87.86%. Out of these 63.4% (n= 78) had a histological diagnosis and these were then correlated with the imaging diagnosis which showed an agreement in 82%. On imaging, focal tumors accounted for 51.2% (n=63) while organomegaly accounted for 48.8% (n=60) of all the masses. On imaging, most tumors were renal in origin accounting for 31.7% of all the focal masses and majority of these were seen between the age of 1 -5 years. Abdominal swelling was the most common presenting symptom (95.9%) and Ultrasound was commonly used as the first imaging modality in 93% of the cases. Wilms tumor (41.2%) and lymphoma (29.6%) were the commonest histological diagnosis encountered. Conclusion The imaging findings in pediatric abdominal masses are varied and numerous. Most children with abdominal masses present with an abdominal swelling. Findings from this study showed that diffuse organomegaly was commonly due to lymphoproliferative disorders and parasitic infections while Wilms tumor/Nephroblastoma was the most common tumor followed by lymphoma. Ultrasound was the most commonly used initial investigation. CT was mainly used for further characterization after ultrasound. Imaging had an overall agreement with the histology in of 82% of the cases; with a higher agreement in diagnosing certain tumors such as Wilms tumor and Ovarian teratoma. Key words: Abdominal masses, abdominal tumors, pediatric abdominal masses, ultrasound, MRI, CT scan