Metastatic atypical fibroxanthoma.

Atypical fibroxanthoma (AFX) is an undifferentiated pleomorphic sarcoma that typically has low-grade malignant potential. Although recurrences do occur, only approximately 25 cases of metastasizing AFX have been reported. Herein a patient with an AFX that metastasized and eventuated in death is described. Although AFX remains a diagnosis of exclusion, through this pedagogic case, the clinical, immunohistochemical, and genetic features that can assist in diagnosis are discussed.