dermatofibroma with pleomorphic cells

Definition : dermatofibroma with monster cells.

Histologic examination :

 characteristic findings of a dermatofibroma, including :

• rete ridge flattening and bridging;
• a stroma containing scattered, large, round, eosinophilic collagen bundles;
• a polymorphous dermal infiltrate of spindle and xanthomatous cells with scattered siderophages.

 Some xanthomatous cells demonstrated features consistent with monster cells, including huge bizarre nuclei and one or more nucleoli.
 Immunohistochemical staining for factor XIIIa is positive.

See also

 Giant dermatofibroma with monster cells. Goodman WT, Bang RH, Padilla RS. Am J Dermatopathol. 2002 Feb;24(1):36-8. PMID: 11803279