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Updated: Apr 9, 2026
Comparative Lesions Analysis Through a Targeted Sequencing Approach
Published on: November 5, 2019
Comprehensive Immunohistochemical Analysis of Atypical Fibroxanthoma: Focus on PRAME in Differential Diagnosis
Gozde Gungor Sahin1, Elif Eroglu1, Nesimi Buyukbabani1,2
1Department of Pathology, Istanbul University, Istanbul Faculty of Medicine, Istanbul, Turkey ; and.
Background:
Atypical fibroxanthoma (AFX) is an uncommon cutaneous neoplasm predominantly affecting elderly individuals in sun-exposed areas. Despite its alarming histopathological features, AFX typically exhibits an indolent clinical course. Diagnosis remains challenging due to overlapping features with other aggressive cutaneous malignancies, especially malignant melanoma.
Methods:
We retrospectively analyzed 15 cases of AFX diagnosed between 2009 and 2024. Comprehensive immunohistochemical profiling was performed, including CD10, CD68, S100, Melan-A, HMB45, CD31, CD34, ERG, cytokeratins, P40, P63, SMA, Desmin, and newly, PRAME (clone EPR20330). Clinical and follow-up data were collected from medical records.
Results:
The cohort had a mean age of 72.9 years, with a male predominance (66.7%). The scalp was the most frequent tumor site (40.0%). All cases demonstrated diffuse block-type CD10 positivity and were uniformly negative for PRAME. Occasional weak staining for melanocytic markers was observed in a minority of cases. After a mean follow-up of 84.0 months, all patients were alive.
Conclusion:
A comprehensive immunohistochemical panel is essential for the accurate diagnosis of AFX. The absence of PRAME expression, together with block-type CD10 positivity, supports the distinction of AFX from malignant melanoma and other histological mimics, facilitating appropriate clinical management.
