Soft Tissues: Lipoma: Chondroid lipoma

2012-06-01   Julia A Bridge , Dali Huang , Janos Sumegi 

1.Department of Pathology, Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-3135, USA



Chondroid lipoma is a benign adipose tissue tumour that features clinical, morphologic, and genetic characteristics that are distinct from the common conventional lipoma.



Chondroid lipoma is a benign lipomatous neoplasm.

Clinics and Pathology


Chondroid lipoma is an extremely rare benign adipose tissue tumour. Most tumours arise in adult women.


Chondroid lipoma primarily occurs in the subcutaneous or deep soft tissues of the proximal extremities and limb girdles, but this lesion may also arise in other sites including the distal extremities, trunk, and head and neck regions (particularly the oral cavity). This tumour typically presents as a painless, slow growing mass. Excision is curative; chondroid lipoma does not recur locally or metastasize.


Chondroid lipomas range from 2 to 11 cm in size and are well delineated, often encapsulated lesions with yellow cut surfaces. Chondroid lipoma is composed of nests and cords of mature adipocytes and uni- or multivacuolated cells resembling lipoblasts embedded in a prominent myxohyaline matrix (Figure 1). Cells with eosinophilic, granular cytoplasms may also be seen. Hemorrhage and fibrosis are common with a prominent vasculature. Histologically, chondroid lipoma may resemble myxoid liposarcoma or extraskeletal myxoid chondrosarcoma. Immunostaining with S100 protein (mature adipocytes) is positive. Intracytoplasmic glycogen is highlighted with PAS stains. Alcian blue and toluidine blue stain the chondroitin sulfate substrate.
Atlas Image
Figure 1. Lower and higher power fields (left and right respectively) of chondroid lipoma.


Atlas Image
Figure 2. Partial karyotype and corresponding schematic illustrating the 11;16 translocation recurrent in chondroid lipoma.

Cytogenetics morphological

Chondroid lipoma is characterized by a t(11;16)(q13;p13) chromosomal translocation that results in fusion of the C11orf95 (11q13) and MKL2 (16p13.3) genes (Figure 2).

Genes Involved and Proteins

Gene name

C11orf95 (chromosome 11 open reading frame 95)



Dna rna description

The C11orf95 (chromosome 11 open reading frame 95) gene consists of 7 exons located within 6961 bp of genomic DNA.

Protein description

C11orf95 codes for a 678 amino acid hypothetical protein of unknown function that exhibits expression in a wide variety of human tissues. This protein contains four C2H2 zinc fingers (classical zinc finger domain) with zinc ion binding molecular function.

Gene name

MKL2 (MKL1/myocardin like 2)



Dna rna description

MKL2 is a member of the myocardin/megakaryoblastic leukemia gene family. The MKL2 gene contains 13 exons and spans more than 195 kb.

Protein description

The MKL2 gene codes for a 1049 amino acid myocardin-like protein. MKL2, an SAP (SAF-A, acinus, and PIAS) DNA-binding domain containing protein, has been functionally implicated in chromatin remodeling in addition to serving as a transcriptional co-activator of SRF (serum response factor).

Result of the chromosomal anomaly

Atlas Image
Figure 3. Wild-type and fusion gene associated with the 11;16 translocation. A: Schematic of C11orf95, MKL2, and C11orf95-MKL2 fusion gene; solid bars represent coding exons, gray boxes are non-translated regions. B: Amino acid sequence at the breakpoint. C: Schematic and domain structure of the fusion C11orf95-MKL2 protein; the letters within the bars designate functional domains: zinc finger C2H2 domain (Znf), proline rich region (P), DNA-binding SAP domain (SAP), and cooled-cooled region (CC).


The 11;16 translocation results in fusion of exons 5 and 9 of the C11orf95 and MKL2 genes respectively.


The C11orf95-MKL2 fusion gene codes for a transcript of 9127 nucleotides with an open reading frame of 3744 nucleotides. The chimeric transcript encodes a protein of 1247 amino acids that retains the SAP domain from MKL2.


The C11orf95-MKL2 chimeric transcript encompasses all putative functional motifs encoded by each gene. The C-terminal portion of the C11orf95-MKL2 chimeric protein contains a SAP DNA-binding domain, a coiled-coiled domain and a proline-rich region known to be present in transcription factors and oncoproteins. Additional studies must be conducted to determine the functionality of the C11orf95-MKL2 fusion oncogene in chondroid lipoma.


Pubmed IDLast YearTitleAuthors
147227642004Chondroid lipoma is characterized by t(11;16)(q13;p12-13).Ballaux F et al
154726602004Lipoma of the oral and maxillofacial region: Site and subclassification of 125 cases.Furlong MA et al
105245341999Unique cytological features and chromosome aberrations in chondroid lipoma: a case report based on fine-needle aspiration cytology, histopathology, electron microscopy, chromosome banding, and molecular cytogenetics.Gisselsson D et al
206077052010C11orf95-MKL2 is the resulting fusion oncogene of t(11;16)(q13;p13) in chondroid lipoma.Huang D et al
88654991996Chondroid lipoma: MRI appearances with clinical and histologic correlation.Logan PM et al
82142551993Chondroid lipoma. A unique tumor simulating liposarcoma and myxoid chondrosarcoma.Meis JM et al
75736891995Chondroid lipoma, a tumor of white fat cells. A brief report of two cases with ultrastructural analysis.Nielsen GP et al
145659522003Megakaryoblastic leukemia-1/2, a transcriptional co-activator of serum response factor, is required for skeletal myogenic differentiation.Selvaraj A et al
99501681999Cytogenetic and cytologic features of chondroid lipoma of soft tissue.Thomson TA et al
226076592012Chondroid lipoma: an update and review.Thway K et al
215592692011Delineation of chondroid lipoma: an immunohistochemical and molecular biological Vreeze RS et al


Julia A Bridge ; Dali Huang ; Janos Sumegi

Soft Tissues: Lipoma: Chondroid lipoma

Atlas Genet Cytogenet Oncol Haematol. 2012-06-01

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