Soft Tissues: Lipoblastoma

2005-01-01   Cristina Morerio , Claudio Panarello 

1.Dipartimento di Ematologia ed Oncologia Pediatrica, IRCCS Istituto Giannina Gaslini, Largo G. Gaslini 5, 16147 Genoa, Italy



Two forms of the tumor lesion have been described: encapsulated circumscribed type (lipoblastoma), and a noncapsulated diffuse infiltrative type (lipoblastomatosis).

Clinics and Pathology

Embryonic origin

Develops from embryonic remnants of white fat tissue.


Primarily occurs in young children (


Presents in superficial tissues of arms and legs (deeper in lipoblastomatosis), though mediastinum, retroperitoneum, trunk, head and neck may be affected.


Lobulated tissue composed of immature fat cells separated by fibro-vascular septa and areas with a myxoid matrix. The lobules contain lipoblasts in different stages of differentiation, ranging from primitive, spindle-shaped cells to lipoblasts simulating mature fat cells. Differential diagnosis, particularly in older children or in diffuse lipoblastoma, include myxoid liposarcoma and atypical lipoma and may be based on distinct cytogenetic abnormalities.


Surgical excision.


These tumors have an excellent prognosis but local recurrence is possible expecially in diffuse lesions.


Cytogenetics morphological

Pseudodiploid karyotype with clonal chromosomal rearrangements involving the 8q11-13 region. Gain of chromosome 8 is reported.

Cytogenetics molecular

Detectable by metaphase and/or interphase FISH using specific PLAG1 probes.
Atlas Image
Dual-color FISH analysis in a case of lipoblastoma with complex structural rearrangement: RP11-140I16 (PLAG1) (red) was cohybrized with RP11-299N14 (HAS2) (green). Arrow indicates PLAG1-HAS2 fusion signal on the der(8), arrowhead indicates the normal chromosome 8. The BAC clones were provided by Prof. M.Rocchi.


RP11-140I16, BAC227k20, YAC164H5, RP11-299N14, YAC947h7.

Genes Involved and Proteins

Gene name

PLAG1 (Pleomorphic adenoma gene 1)



Dna rna description

7313 bp mRNA

Protein description

PLAG1, (together with PLAGL1 and PLAGL2), belongs to a subfamily of C2H2 zinc finger transcription factors that activate transcription.

Gene name

HAS2 (hyaluronan synthase 2)



Gene name

COL1A2 (collagen, type I, alpha 2)



Result of the chromosomal anomaly


HAS2-PLAG1, COL1A2-PLAG1 Chromosomal rearrangements in tumor tissue determine PLAG1 transcriptional up-regulation.


5 COL1A2 - 3 PLAG1 has been described in one case of t(7;8)(p22;q13)


Alternative splicing variants which included or lacked PLAG1 exon 2.


HAS2-PLAG1 and COL1A2-PLAG1 both encode a full-lenght PLAG1 protein.


Pubmed IDLast YearTitleAuthors
108119812000Evidence of involvement of the PLAG1 gene in lipoblastomas.Astrom A et al
112728912000Evidence by spectral karyotyping that 8q11.2 is nonrandomly involved in lipoblastoma.Chen Z et al
43530201973Benign lipoblastomatosis. An analysis of 35 cases.Chung EB et al
115495882001PLAG1 alterations in lipoblastoma: involvement in varied mesenchymal cell types and evidence for alternative oncogenic mechanisms.Gisselsson D et al
117198762001Lipoblastoma and lipoblastomatosis: a report of two cases and review of the literature.Harrer J et al
109873002000PLAG1 fusion oncogenes in lipoblastoma.Hibbard MK et al
122425282002Atypical lipomatous tumor in a 14-year-old patient: distinction from lipoblastoma using FISH analysis.Kuhnen C et al
156424022005PLAG1-HAS2 fusion in lipoblastoma with masked 8q intrachromosomal rearrangement.Morerio C et al
95303331998Lipoblastoma: a case with t(7;8)(q31;q13).Panarello C et al
150663172004Updates on the cytogenetics and molecular genetics of bone and soft tissue tumors: lipoma.Sandberg AA et al
34568281986Chromosome abnormalities in two benign adipose tumors.Sandberg AA et al


Cristina Morerio ; Claudio Panarello

Soft Tissues: Lipoblastoma

Atlas Genet Cytogenet Oncol Haematol. 2005-01-01

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