Liposarcoma in a Child: A Case Report

Pediatric liposarcoma: A case series and literature review

Liposarcoma is arare soft tissue sarcoma in children. While prognosis, clinical behavior, and response to therapy among the various histologic subtypes are well described in adults, data in children are limited. Here, we describe our experience treating 14 children with liposarcoma at a large, academic pediatric center and review the available pediatric literature. This comprehensive report adds treatment, survival, and genomic data to pediatric liposarcoma literature.

Liposarcomas in young patients: a study of 82 cases occurring in patients younger than 22 years of age

Liposarcomas typically occur in middle aged to older adults. Altogether, approximately 50 bona fide liposarcomas have been reported in children and adolescents, most of which have represented myxoid liposarcomas, with a good prognosis. We undertook a retrospective study of 82 liposarcomas occurring in patients below 22 years of age. Clinicopathologic and follow-up information was obtained. Fluorescence in situ hybridization for FUS, EWSR1, CHOP (DDIT3), and MDM2 was performed in 30 cases. The tumors occurred in 28 males and 54 females (5 to 22 y of age) and involved many locations. Fifty-six cases were typical myxoid liposarcomas, including 2 with round cell areas. The tumors were grade 1 (56 cases) and grade 3 (2 cases). Thirty-seven of 38 patients with follow-up are alive without disease and 1 is alive with disease (median 59 mo follow-up duration, range: 8 to 108 mo). Six cases showed myxoid liposarcoma with spindled growth ("spindle cell myxoid liposarcoma"); these arose in 5 females and 1 male (median age 14 y) and involved the thigh in 40% of cases. All were grade 1. Follow-up (4 of 6 patients) showed local recurrences in 2 cases and metastases in 1 case. Twelve tumors consisted of conventional myxoid liposarcoma and pleomorphic liposarcoma ("pleomorphic myxoid liposarcoma"); these arose in 4 males and 8 females (10 to 22 y of age) and often involved the mediastinum. Tumor grades were 2 (4 cases) and 3 (8 cases). Follow-up (10 patients) showed 7 dead of disease, 1 alive with disease, and 2 disease free. Four atypical lipomatous tumors were seen including 2 with low-grade dedifferentiation. Two local recurrences were seen; all patients are disease free. Two conventional pleomorphic liposarcomas were seen; 1 patient with follow-up is disease free. FUS-CHOP and EWSR1-CHOP rearrangements were identified by fluorescence in situ hybridization in 15/23 and 2/23 conventional myxoid liposarcomas, respectively, and in no other tumors. Amplification for MDM2 was absent in all cases. We conclude that conventional myxoid liposarcoma is by far the most common subtype of liposarcoma in young patients, with an excellent prognosis. Two apparently novel subtypes of liposarcoma, termed pleomorphic myxoid liposarcoma and spindle cell myxoid liposarcoma comprise considerable percentages of liposarcomas in this age group and should be distinguished from conventional myxoid liposarcoma and conventional pleomorphic liposarcoma. Pleomorphic myxoid liposarcoma and spindle cell myxoid liposarcoma most likely represent high-grade and low-grade variants of myxoid liposarcoma, respectively. Additional study of such cases will be necessary for definitive classification.

Cytological features of lipoblastoma: A report of three cases

Lipoblastoma is a rare benign neoplasm occurring mostly in children under the age of three. Accurate preoperative diagnosis is mandatory for planning the treatment. The main aim of this study is to establish the cytological features of lipoblastoma and to answer the question: "Is cytological diagnosis of lipoblastoma reliable?"Preoperative fine-needle aspiration biopsy (FNAB) and tissue sections of three children treated for lipoblastoma at the Division of Pediatrics, University Medical Center, Ljubljana, Slovenia, in the period from 1997 to 2004 were reexamined. The Giemsa- and Papanicolaou-stained FNAB smears were moderately or poorly cellular and contained lipocytes, lipoblasts, and spindle cells in various proportions. The tumor cells were in clusters and tissue fragments or as single cells. Thin branching capillaries were observed in most of the clusters and tissue fragments. In the background, abundant myxoid extracellular material and naked oval nuclei were present. In the first case, the cytological diagnosis was benign soft-tissue tumor, in the second the diagnosis was not conclusive and the last case was correctly diagnosed as lipoblastoma. In the differential diagnosis of the second case, both lipoblastoma and liposarcoma were considered cytologically as well as histologically. At 7-yr follow-up, there is no evidence of the disease.Thus, we conclude that lipoblastoma with typical cytological features could be accurately diagnosed by FNAB. However, tumors containing numerous lipoblasts could pose a diagnostic problem.

Lipoblastoma and lipoblastomatosis: a clinicopathological study of 14 cases

The clinicopathological features of 14 cases of lipoblastoma and lipoblastomatosis are presented. The age of the patients at presentation ranged from 5 days to 6 years (mean 2.7 years); nine patients were male. Histologically, six cases were circumscribed (lipoblastoma) while eight were diffuse and ill-defined (lipoblastomatosis). In both groups and in individual cases there was distinct lobulation, as well as a spectrum of adipocytic maturation. Cytologically, the 10 most mature lesions were composed of uniform adipocytes intermixed with only scattered lipoblasts and primitive mesenchymal cells. A notable feature in the other four cases was a prominent myxoid stroma producing a very close resemblance to myxoid liposarcoma. Mitotic figures were rare and always normal in appearance. Atypical nuclei were not evident. Follow-up in eight patients revealed local recurrence in two. Liposarcoma in patients under 10 years is exceedingly rare, and, in myxoid form, may be almost impossible to distinguish histologically from lipoblastoma. Helpful clues are the lack of lobulation, variable growth pattern and increased nuclear atypia in liposarcoma.