Pleomorphic fibroma of the skin with MDM2 immunoreactivity: A potential diagnostic pitfall

Mehrnoosh Tashakori, Jason Pimentel, Brooke E. Howitt, Jessica Sanchez, Susan Michalowski, Dhananjay Chitale, Adrian H. Ormsby, Sean R. Williamson

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Pleomorphic fibroma is a rare benign cutaneous neoplasm characterized by spindle-shaped cells and multinucleated giant cells scattered throughout collagenous stroma. These morphologic features can lead to diagnostic confusion, including atypical lipomatous tumor as one consideration. In contrast to atypical lipomatous tumor, previous studies have found pleomorphic fibroma to be negative for MDM2 immunohistochemical staining and MDM2 gene amplification. Here, we present a case of pleomorphic fibroma of skin with nuclear MDM2 immunoreactivity in the absence of MDM2 gene amplification, underscoring the superiority of fluorescence in situ hybridization as a diagnostic test in this differential diagnosis. The RB1 locus is also explored for differential diagnosis with pleomorphic/spindle cell lipoma and related entities.

Original languageEnglish (US)
Pages (from-to)59-62
Number of pages4
JournalJournal of cutaneous pathology
Issue number1
StatePublished - Jan 2018
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd


  • MDM2
  • fluorescence in situ hybridization
  • immunohistochemistry
  • pleomorphic fibroma


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