Lipoblastoma: Pathophysiology and Surgical Management By Anthony V. Dilley, Dimple L. Patel, M. John Hicks, and Mary L. Brandt Houston, Texas Background/Purpose: Lipoblastoma/lipoblastomatosis is a poorly understood and uncommon soft tissue tumor of in- fancy and early childhood. Twenty-four patients that pre- sented to a single institution over a 15-year period were reviewed for clinical features and outcome. Methods: A retrospective review was conducted. Results: Twenty-five cases were identified; 1 chart was not available for review. Fourteen girls and 11 boys with a me- dian age of 20 months (2 months, 10 years) presented with 26 separate tumors. Nineteen were focal and 7 diffuse. The tumors were located on the trunk (n = 13), leg (n = 6), arm (n = 3), and head and neck (n = 4). Five patients (all with diffuse type) had up to 3 recurrences. Conclusions: Patients with focal lipoblastoma are unlikely to require further surgery after initial resection. Patients with diffuse lipoblastoma (lipoblastomatosis) are likely to have recurrent disease (usually within 2 years) and should un- dergo close follow-up. Genetic analysis of the specimen will help exclude liposarcoma. Recurrent lesions are best imaged with magnetic resonance imaging to assess extent and plan reconstruction if necessary. J Pediatr Surg 36:229-231. Copyright © 2001 by W.B. Saunders Company. INDEX WORDS: Lipoblastoma, iipoblastomatosis, benign, soft tissue tumors, adipose tumor. IPOBLASTOMAS and their diffuse form, lipoblas- tomatosis, are uncommon tumors of infancy and early childhood. They are benign, but can recur, often requiring multiple excisions. Many surgeons first learn of the lesion when they read the pathology report of a patient in whom they thought a lipoma had been excised. The report by Vellios et al 1 in 1958 was the first recent attempt to characterize these tumors, and further series have been published subsequently. 2-4 There were earlier descriptions of lipoblastoma that did not use the current nomenclature, such as the report by Jaffee5 in 1926. Reports since 1958 have included assessments of clinical presentation, clinical associations, and imaging tech- niques, with suggestions as to how these tumors should be approached. Because the natural history of this con- dition still appears to be ill defined, we reviewed our 15 year experience of 25 patients with this condition and found it to be comparable with the largest single institu- tional cohort reported thus far (24 patients collected over 40 years at the Children's Hospital of Philadelphia). 2 Some demographic features of our series contradict those of previous reports. In addition, advances in imaging and cytogenetics have occurred in recent years, changing our understanding of this tumor. MATERIALS AND METHODS Twenty-five cases of lipoblastoma and lipoblastomatosis collected in a single institution over 15 years (1985 through 1999) were reviewed retrospectively. Clinical notes were examined and all radiology, oper- ative, and pathology reports reviewed. Age, gender, and ethnicity were noted, as well as features of the lesion such as the side and site, whether it was focal or diffuse, and whether a recurrence had occurred. Asso- ciated anomalies, when present, were noted. RESULTS There were 14 girls and 11 boys ranging in age from 2 months to 10 years. The chart of 1 boy was unavailable for review, and he was excluded from analysis. The median age of the remaining 24 patients was 20 months. The most common presenting symptom was a painless mass increasing in size (12 of 24). Six patients presented with a persistent mass without a noticeable change in size, 4 with hernias (3 inguinal and 1 epigastric), 1 with abdominal pain, and 1 with vomiting and lethargy. Two patients had 2 separate tumors, and 22 had a single tumor, for a total of 26 tumor resections. Thirteen lesions were right sided, 9 left sided, and 4 central (midline). The tumors were most commonly on the trunk (n = 13, includes retroperitoneum In = 3], peritoneal cavity [n = 1], and inguinal canal [n = 3]), 9 were found on the extremities (arm, n = 3; leg, n = 6), and 4 were resected from the head and neck region. Nineteen of the 26 lesions were focal or circumscribed tumors, and 7 were lipoblastomas of the diffuse type (lipoblastomatosis). Five of the 7 patients with the diffuse type required 1 or more reexcisions (14 procedures in 7 patients). All of the From the Departments of Surgery and Pathology, Baylor College of Medicine, Houston, TX. Presented at the 31st Annual Meeting of the American Pediatric Surgical Association, Orlando, Florida, May 25-29, 2000. Address reprint requests to Mary L. Brandt, MD, Department of Surgery, Texas Children's Hospital, 1102 Bates, Suite 245, Houston, TX 77O30. Copyright © 2001 by W.B. Saunders Company 0022-3468/01/3601-0042503. 00/0 doi: 10.1053/jpsu.2001.20060 Journal of Pediatric Surgery, Vol 36, No 1 (January), 2001 : pp 229-231 229