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Liposarcomatous differentiation in malignant phyllodes tumours is unassociated with MDM 2 or CDK 4 amplification
Author(s) -
Lyle Pamela L,
Bridge Julia A,
Simpson Jean F,
Cates Justin M,
Sanders Melinda E
Publication year - 2016
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/his.12898
Subject(s) - liposarcoma , pathology , sarcoma , undifferentiated pleomorphic sarcoma , biology , myxoid liposarcoma , cancer research , soft tissue sarcoma , medicine
Aims Breast sarcomas are rare, usually occurring in the setting of malignant phyllodes tumour ( MPT ). Heterologous differentiation commonly resembles well‐differentiated or pleomorphic liposarcoma. In extramammary sites, these subtypes have different biological behaviours and distinct genetic alterations: MDM 2 and CDK 4 amplification in well‐differentiated liposarcoma, and polyploidy with complex structural rearrangements in pleomorphic liposarcoma. The aim of this study was to investigate foci resembling well‐differentiated liposarcoma in MPT for MDM 2 and CDK 4 amplification. Methods and results We evaluated the clinicopathological characteristics of MPT s received by the Vanderbilt Breast Consultation Service containing components resembling well‐differentiated or pleomorphic liposarcoma. Cases with available tissue blocks were subjected to fluorescence in‐situ hybridization with MDM 2 and CDK 4 probes. Thirty‐eight MPT s with liposarcomatous components were available for review. The mean patient age was 49.8 years (range 26–84 years). In addition to well‐differentiated liposarcoma, the following components were also present: high‐grade undifferentiated sarcoma ( n = 9; 23.7%), pleomorphic liposarcoma ( n = 4; 10.5%), non‐high‐grade sarcoma not otherwise specified ( n = 22; 57.9%), and malignant peripheral nerve sheath tumour‐like ( n = 2; 5.2%). Among 10 cases tested, none showed amplification of MDM 2 or CDK 4 . Conclusions This study examined molecular changes in the well‐differentiated liposarcomatous components of MPT . Despite histological similarity to well‐differentiated liposarcoma of soft tissues, liposarcomatous differentiation in MPT lacks the molecular phenotype characteristic of extramammary well‐differentiated liposarcoma.