Significance of Stromelysin 3, Apolipoprotein D ve CD34 immunohistochemical markers in diagnosis of dermatofibroma, dermatofibrosarcoma protuberans and dermatofibrosarcoma protuberans with fibrosarcomatous transformation

In this study age, gender, size of tumor and histopathological features were compared in DF (n:24), DFSP (n:26) and DFSP-FS (n:12) groups. Also, staining properties of these tumors with Apo D, CD34 and ST3 were evaluated for diagnosis and differential diagnosis. Our results reveal that age, tumor localization and size are different among DF, DF-SP and DFSP-FS groups. Some properties like localization of tumor in the trunk, greater size of tumor and older age of patient seem to be associated with malignancy. Some histopathological features like subcutaneous involvement with honeycomb pattern, distinctive storiform pattern, arrangement with fascicular herringbone pattern, atrophy in epidermis and extension to epidermis without any intact dermal zone, and high mitotic ratio are found to support malignancy. It is important to note ?DFSP + fibrosarcoma? or ?DFSP with fibrosarcomatous transformation? in pathology report to alert clinician because of prognosis and treatment protocols of these tumors are not clear and some reports suggest that these lesions could behave more aggressive. CD34 is still found to be the most relevant immunohistochemical marker in differential diagnosis. Positive CD34 staining supports DFSP while negative results turn the way to DF. Strong and diffuse ST3 staining exists mostly in DF lesions. But in our study ST3 staining ratio in DFSP?s is found to be higher than previous studies, rising the conclusion that ST3 staining alone is not adequate for diagnosis. Therefore weak ST3 staining must not be considered as significant and only negative staining for ST3 can be used to rule out DF. Apo D staining pattern in DFSP group is quite similar to CD34 while no staining was observed in DF group. This finding suggests that Apo D staining may be useful for DFSP diagnosis together with CD34. It is concluded that CD34 staining is of great value in differantiating malignant and benign cutaneous fibrohistiocytic lesions, especially if used together with Apo D and ST3; while none of these markers are capable to differentiate malignant cutaneous fibrohistiocytic lesions (DFSP and DFSP-FS) or defining FS areas within DFSP. Diagnosis of fibrosarcomatous transformation areas still depends on determination of herringbone fascicular arrangement of spindle cells, prominent nuclear atypia, pleomorphism and high mitotic activity observed in haematoxylene&eosin stained sections.