Palpable inguinal mass in children should be differentiated from inguinal hernia, hydrocele, lymph node, and tumor. Though using ultrasonography, fatty tumor would be misdiagnosed as incarcerated inguinal hernia containing fatty component. We experienced the huge inguinal lipoblastoma in 5-year-old girl mimicking recurrent incarcerated hernia. Laparoscopic exploration revealed it was not incarcerated hernia but well demarcated bulging mass from abdominal wall. Mass was about 10×4×3 cm and extended from internal inguinal ring to saphenous opening. It was near total excised because of right external iliac vein injury. Pathologically, it was proven as lipoblastoma containing mature adipocyte with lipoblast and fibrous septa. Postoperatively, we noticed a segmental thrombotic occlusion of external iliac vein. After 1 year, she has no symptom related to occluded vessel. The remained lipoblastoma showed no interval change. Even lipoblastoma has a good prognosis with low recurrence rate, we need careful follow-up.

Lipoblastoma is a rare benign soft tissue tumor occurring in infancy and early childhood. It is characterized by fat lobules with varying degrees of maturity, multivaculoated lipoblasts, fibrocapillary networks and myxoid stroma. Lipoblastoma has a good prognosis with no metastases despite its potential for local invasion. From Jan, 1990 through April, 2007, 12 children underwent the operation for lipoblastoma, 7 boys and 5 girls, diagnosed at median 22 months (5~43 months). Median follow up was 6 year 7 months. Primary sites included back (n=5), intraabdominal (n=2) and one in each of buttock, chest wall, neck, nose and scalp. Tumors presented with a growing mass in 9 patients, abdominal distension in 2, and an incidental finding on chest radiography in one. Complete excisions were done in all patients. There was one recurrence in a patient with a scalp mass. After reoperation, he has been doing well without evidence of recurrence. Lipoblastoma has a favorable prognosis, but recurrence can occur even with complete excision. Regular follow up is necessary to detect recurrences.