Intrathoracic Pleomorphic Liposarcoma in a Child: Study of an Unusual Case

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.

Liposarcoma in children and young adults: a clinicopathologic and molecular study of 23 cases in one of the largest institutions of China

The incidence of pediatric liposarcoma is rare and most published cases lack systematic genetic analyses. We present clinicopathologic and genetic features of 23 liposarcomas aged <22 years. The study cohort comprised 10 males and 13 females (M:F=1:1.3) aged 11-21 years (median 17 years). The tumors predominantly occurred at the extremities (16/23; 69.6%), followed by the head/neck (2/23; 8.7%), chest (2/23; 8.7%), waist (2/23, 8.7%), and retroperitoneum (1/23; 4.3%). The tumor subtypes were sixteen myxoid liposarcoma (ML), one well-differentiated liposarcoma (WDL), two dedifferentiated liposarcoma (DDL), one pleomorphic liposarcoma (PL), and three myxoid pleomorphic liposarcoma (MPL) cases. Fluorescence in situ hybridization analysis identified MDM2/CDK4 amplification in all WDL/DDL cases (3/3; 100%) and DDIT3 rearrangement in all ML cases (13/13; 100%). Whole-exome sequencing indicated that one PL case and one MPL case exhibited RB1 loss. The two tested MPL cases had TP53 mutation and one of them harbored a TP53 germline mutation. Follow-up information was available for 20 patients (20/23; 87.0%) with a median follow-up duration of 42.5 months (range, 13-120 months). Three patients exhibited tumor progression (3/20;15.0%). Seventeen patients (17/20; 85.0%) survived with no evidence of disease. One MPL case (1/20; 5.0%) died of the disease. In conclusion, despite some overlaps, the occurrence, distribution of subtype, and prognosis of liposarcoma are overall different in children and adults. Most MLs and ALT/WDL/DDLs showed similar genetic aberrations with adult counterparts. Molecular features of MPL overlapped with those of conventional PL. The genetic characteristics including Tp53 status of MPL need further investigation.

Primary Liposarcoma of Bone in an Adolescent

We report the clinicopathologic and cytogenetic findings in an unusual case of primary liposarcoma of bone. A 16-year-old girl presented with a destructive, osteolytic tumor of the proximal humerus. Upon biopsy, the tumor was highly anaplastic and necrotizing and was initially considered to be consistent with osteosarcoma. Following chemotherapy, there was 100% tumor necrosis in the resection specimen. Twentyeight months later, solitary supraclavicular and pulmonary metastases appeared with the morphologic features of pleomorphic liposarcoma. Retrospective review of the bone biopsy showed scattered lipoblasts and no unequivocal malignant osteoid. Ghost-like remnants of necrotic liposarcoma were seen in the resection specimen. Cytogenetic analysis of a metastatic lesion showed complex karyotypic abnormalities. Awareness of the existence of primary bone sarcomas with lipogenic differentiation expands the differential diagnosis of malignant bone tumors including cases in the pediatric population. This is the first report of cytogenetic findings in this tumor.

Orbital pleomorphic liposarcoma in an eight-year-old boy

Adult-type sarcomas are, as the name indicates, rare tumors in the pediatric population. Although soft tissue sarcomas as a group are not uncommon diagnoses, nonrhabdomyosarcoma soft tissue sarcomas are much rarer and encompass a wide range of diagnoses. A few of these tumors are commonly found in the adult population and are thus referred to as adult-type sarcomas. We present a case of a pleomorphic liposarcoma, an adult-type sarcoma, arising as a primary tumor in the orbit of an 8-year-old boy. The histologic analysis revealed bizarre tumor giant cells and definitive lipoblastic differentiation. The atypical cells were positive for S100, and negative for CD34, desmin, MyoD1, and myogenin. This is a high-grade sarcoma, very rarely encountered in the pediatric population. We present the histologic findings of this unusual pediatric sarcoma and review the 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.