Metastasizing Atypical Fibroxanthoma (Cutaneous Malignant Histiocytoma): Report of Five Cases

BACKGROUND: Atypical fibroxanthoma (AFX) is an unusual malignant fibrohistiocytic tumor of sun-damaged skin. When first described, it was felt to be a reactive tumor of low malignant potential. More recently, it has been shown to be a tumor of intermediate malignant potential. OBJECTIVE: To describe five cases of metastatic AFX. RESULTS: Five patients ranging in age from 65 to 85 years old presented with metastatic AFX. Three of the five cases presented with regional lymph node disease. Also, three of the five cases had other aggressive cutaneous malignancies. LN-2 (CD74) staining was positive in three of five primary tumors and two of five metastatic tumors. CONCLUSION: The metastatic potential of AFX may be underestimated. LN-2 staining may be a useful marker in identifying more aggressive tumor behavior.