Lipoblastoma Mimicking Inguinal Hernia

Lipoblastoma is a rare benign soft tissue tumor occurring mostly in infancy and early childhood. It arises from white embryonic fat. Adipose tissue tumors constitute about 6% of all soft tissue neoplasms in children and lipoblastoma accounts for only 5 to 30% of adipose tissue tumors.[1-3] Many patients present with a painless mass, which lead to misdiagnosis. A 2-year old girl was admitted with an asymptomatic progressively enlarging swelling at the right inguinal region for 4 months. There were no obstructive bowel symptoms. She had a history of right inguinal hernia repair 8 months ago (operative notes were not available). On physical examination, a non-tender, mobile and irreducible (2x3 cm) swelling was noted. Inguinal ultrasonography was normal. Patient underwent surgical exploration of the swelling through the old scar with the initial diagnosis of recurrent sliding inguinal hernia of ovary. At operation, there was no recurrence of inguinal hernia and the inguinal swelling was more like a mass. The tumor was completely excised, with the resulting specimen of 4 x 2.5 x 2cm, with no invasion into the surrounding tissues. The histopathological examination revealed lobulated tissue composed of immature fat cells separated by fibro-vascular septa and areas with a myxoid matrix. The lobules contained lipoblasts in different stages of differentiation, ranging from primitive, spindle-shaped cells to lipoblasts simulating mature fat cells (Fig.1). She has been followed up every 3 months for 2 years and no recurrence has occurred.