Molecular pathology of ADIPOCYTIC TUMORS – based on WHO 2020 Soft tissue and bone tumors.
The pathogenesis of lipomas is related to reactivated expression of the HMGA2 protein, which plays a role in the development of the mesodermal lineage during embryogenesis
- ANGIOLIPOMA– The majority (80%) have been reported to have low-frequency PRKD2 mutations.
- CHONDROID LIPOMA– is characterized by a recurrent t(11;16) (q13;p13) chromosomal translocation.
- SPINDLE CELL/PLEOMORPHIC LIPOMA: is characterized 13q deletions /RB GENE.
- MYOLIPOMA: Cytogenetic alterations of the HMGA2 gene have been reported in a few cases
- Atypical lipomatous tumour/well differentiated liposarcoma: characterized by supernumerary ring and giant marker chromosomes,containing amplified sequence of MDM2
- DEDIFFERENTIATED liposarcoma– Amplified MDM2
- MYXOID LIPOSARCOMA– Translocations producing FUS-DDIT3 or rarely EWSR1-DDIT3 fusion transcripts are pathognomonic
- PLEOMORPHIC LIPOSARCOMA: Complex karyotypes. . The most frequent mutations involve TP53 and NF1.
OTHER ADIPOCYTIC TUMORS
- HIBERNOMA: Cytogenetically, almost all hibernomas have breakpoints in chromosome arm 11q, with a distinctive clustering to 11q13.
- LIPOBLASTOMA: The most common numerical change is one or more extra copies of chromosome 8, with or without concurrent rearrangement of 8q11-q13
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