Atypical spindle cell/pleomorphic lipomatous tumour: a clinicopathologic, immunohistochemical and molecular study of 55 cases, highlighting TP53 gene alterations as a genetic hallmark of atypical pleomorphic lipomatous tumour

APLTs predominantly harbour a TP53 alteration in contrast to ASLT cases. Our findings support the classification of APLT as a distinct (sub)entity within a spectrum that overlaps with ASLT, and it remains to be determined whether the broader term 'ASPLT' will hold up. Furthermore, p53 immunostaining proved to be a potentially valuable diagnostic tool, aiding pathologists in differentiating between ASLT and APLT.