Mesenteric panniculitis is an inflammatory and fibrotic process in the mesenteric adipose tissue with unknown etiology. It is rarely seen in general, particularly in children. Etiology is unknown, and pathophysiology is not clear. Factors that trigger the disease are malignancy, tuberculosis, trauma, medications and past surgical interventions. There is no pediatric case series in the literature except single case reports. This paper consists of 3 cases: The first case is a 5-month-old girl, the youngest patient in the literature, who was referred to a pediatric surgeon with vomiting and abdominal distention. She had diffused intraabdominal fluid and mesenteric panniculitis documented by perioperative biopsy. The second case had acute abdominal pain with perforated appendicitis, who eventually had mesenteric panniculitis in the evaluation of the pathological specimen. The last case had a diagnosis of polyarticular juvenile idiopathic arthritis (JIA), successfully treated with etanercept, and has been in remission for 2 years. Interestingly, in one of her routine visits, she had pallor, anemia and renal failure. Bilateral hydronephrosis was detected. Magnetic resonance imaging (MRI) of the abdomen revealed retroperitoneal fibrosis, and mesenteric panniculitis was the histopathological diagnosis.

Keywords: biologics, children, mesenteric panniculitis