Abstract
RATIONALE: Lipomatous tumors are rare in the pediatric population. Lipomatous tumors may develop at any location throughout the body; however, they are highly uncommon in the retroperitoneal area. Lipomatous tumors represent the predominant category of soft-tissue neoplasms. Only 3 cases of pediatric retroperitoneal lipoma have been reported since 1980. We report a benign retroperitoneal lipomatous tumor and the literature compilation of benign retroperitoneal lesions. PATIENT CONCERNS: A 2-year-old South Asian female presenting with 13 months of increasing abdominal distention and intermittent fever was referred to our hospital. The child had no trauma or gastrointestinal symptoms like vomiting, diarrhea, or constipation. DIAGNOSES: An abdominal ultrasound showed a large, echogenic mid-abdomen tumor. The tumor obscured the bowel without calcification or fat necrosis. A color Doppler scan indicated no blood flow in the lesion. The computed tomography scan of the neck, chest, and abdomen with IV contrast showed a well-circumscribed, non-enhancing, heterogeneous hypodense mass from the left hypochondrium to the pelvis on the left abdominal region. The mass measured 18.4 × 14.8 × 13.6 cm, and its Hounsfield units ranged from -66 to -90, indicating adipose tissue. Histopathology showed a benign lipoma made of mature fat cells and thinsultory fibrils with no malignancy, cellular atypia, or necrosis. INTERVENTIONS: The patient had surgical resection via laparotomy, achieving complete resection with negative margins. OUTCOMES: The patient was discharged on the 4th day after the procedure, after an uneventful recovery. After 6 weeks, the child was asymptomatic in follow-up. LESSONS: The long-term prognosis of the retroperitoneal lipoma among children remains inadequately characterized relative to adults due to a small number of cases. Current literature suggests magnetic resonance imaging, computed tomography scan, and FISH are the most suitable diagnostic options. Extended follow-up is essential in pediatric patients.