Diagnostic utility of low-affinity nerve growth factor receptor (P 75) immunostaining in atypical fibroxanthoma

Abstract

We confirmed that CD99 and CD10 are frequently expressed in AFX (65 and 85%, respectively) and that CD31 rarely stains positive (5%). The 50% positivity rate of D2-40, in contrast with published evidence for its absence in melanoma, suggests that D2-40 may be useful for distinguishing AFX from melanoma. Furthermore, because only one sample was positive for p75, we confirm that p75 is useful in differentiating AFX from spindle cell melanoma. We advocate adding p75 and D2-40 to assist in differentiating AFX from melanoma.