Lessons learnt from MDM2 fluorescence in-situ hybridisation analysis of 439 mature lipomatous lesions with an emphasis on atypical lipomatous tumour/well-differentiated liposarcoma lacking cytological atypia.
Histopathology
; 80(2): 369-380, 2022 Jan.
Article
em En
| MEDLINE
| ID: mdl-34523152
ABSTRACT
AIMS:
Amplification of the murine double minute-2 (MDM2) gene, which is usually detected with fluorescence in-situ hybridisation (FISH), is the key driving event for atypical lipomatous tumours (ALTs)/well-differentiated liposarcomas (WDLs). We sought to determine the concordance between the histopathological findings and MDM2 FISH in the diagnosis of ALT/WDL, and to identify the histological features of MDM2-amplified tumours lacking classic atypia. METHODS ANDRESULTS:
We performed a retrospective analysis of all mature lipomatous lesions subjected to MDM2 FISH analysis at our institution. MDM2 FISH analysis was performed on 439 mature lipomatous lesions 364 (82.9%) were negative and 75 (17%) were positive. In 17 of 75 (22.6%) ALTs/WDLs, cytological atypia was not identified on initial histological assessment, thus favouring lipoma. On review, these cases shared common histological features, consisting of a very low number of relatively small stromal cells within the tumour lobules, with mildly coarse chromatin and oval nuclei, admixed with unremarkable adipocytes in a tumour background devoid of fibroconnective septa, areas of fibrosis, or blood vessels. These cells matched the cells in which FISH showed MDM2 amplification. In contrast, 13 cases (3.5%) regarded as suspicious for ALT/WDL on the basis of histology lacked MDM2 amplification and were reclassified following the FISH findings.CONCLUSIONS:
We conclude that a subset of lipoma-like ALTs/WDLs are not associated with any of the features typically described in ALT/WDL. Our study also showed that tumours >100 mm are more likely to be ALT/WDL; however, a history of recurrence or concerning clinical/radiological features was not significantly associated with classification as ALT/WDL.Palavras-chave
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Base de dados:
MEDLINE
Assunto principal:
Neoplasias de Tecidos Moles
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Proteínas Proto-Oncogênicas c-mdm2
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Lipoma
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Lipossarcoma
Tipo de estudo:
Observational_studies
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Prognostic_studies
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Risk_factors_studies
Limite:
Adult
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Aged
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Humans
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Middle aged
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article