Value of CD10 Expression in Differentiating Cutaneous Basal from Squamous Cell Carcinomas and Basal Cell Carcinoma from Trichoepithelioma

Background: In addition to the well-defined histological criteria for squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), immunohistochemical techniques can be used in difficult cases for their differentiation. As differential diagnosis between trichoepithelioma (TE) and BCC is sometimes difficult for the clinician and the pathologist, CD10 may be a useful marker for definite diagnosis. We aimed to evaluate the usefulness of this marker in the differentiation between SCC and BCC and also in the differentiation between BCC and TE. Methods: Fifty-five BCC cases, 50 SCC cases, and 20 cases of benign adnexal tumor with follicular differentiation were retrieved from the archives of the pathology departments of hospitals affiliated with Shiraz University of Medical Sciences. Immunohistochemistry for CD10 was performed on the sections obtained from formalin-fixed, paraffin-embedded blocks. CD10 immunoreactivity in the stroma and/or tumor cells was determined as follows: negative (0); 1+(10-50% positive cells); and 2+(>50% positive cells). Results: Comparison of CD10 expression between the BCC and SCC groups showed a significant difference (P<0.001) in each of the tumor and stromal cells. Comparison of CD10 expression between the BCC and TE groups demonstrated a significant difference in both the tumor and stromal cells (P<0.001). There was no significant difference in CD10 expression between the stromal and tumor cells of the BCC subtypes. Conclusion: CD10 is a useful adjunct marker in distinguishing TE from BCC. CD10 is suggested to be one of the useful immunohistochemical markers to differentiate BCC from SCC.