[518] Expression of CD10 and MMP-11 in the Differential Diagnosis of Dermatofibroma Variants and Dermatofibrosarcoma Protuberans

Changqing Ma, Smita Krishnamurthy, Louis P Dehner, Dongsi Lu. Washington University in St. Louis, St. Louis, MO

Background: Dermatofibrosarcoma protuberans (DFSP) is a fibrohistiocytic tumor of intermediate malignancy and carries significant risk of local recurrence. The distinction between DFSP and dermatofibroma (DF), especially its variants (VDF), can be challenging. CD10 and MMP-11 were found to be useful markers for the differential diagnosis of classical DF and DFSP. We sought to characterize the staining patterns of CD10 and MMP-11 in a large set of VDF and study the utility of these two stains in differential diagnosis of VDF and DFSP.
Design: Immunohistochemical (IHC) stains were performed on 31 cases of DFSP, 38 cases of DF, and 41 cases of VDF using antibodies to CD34, Ki67, CD10, and MMP-11. Of 41 VDF cases, 18 were aneurismal type, 16 lipidized type, 4 with both aneurismal and lipidized features, 1 cellular type, 1 with monster cells, and 1 atypical fibrous histiocytoma.
Results: Thirty-six of 41 (88%) VDF cases and 37 of 38 (97%) DF cases were CD34 negative but only 2 of 31 (6%) DFSP cases showed no staining of CD34. All DFSP cases were positive for Ki67 and 22 of 31 (71%) cases had positive Ki67 stain in 5% or more tumor cells. Comparable staining patterns were observed in 5 of 41 (12%) VDF cases and 1 of 38 (3%) DF cases. CD10 and MMP-11 staining results were shown in Table 1.

Table1. CD10 and MMP-11 Expression in DFSP, DF, and VDF
 CD10MMP-11
IHC results (% of tumor cells positive)DF (38)VDF (41)DFSP (31)DF (38)VDF (41)DFSP (31)
0%2.6% (1)0% (0)9.7% (3)0% (0)0% (0)77.4% (24)
1 - 10%0% (0)0% (0)29.0% (9)2.6% (1)34.2% (14)16.1% (5)
10 - 25%10.5% (4)7.3% (3)22.6% (7)2.6% (1)7.3% (3)6.5% (2)
25 - 50%23.7% (9)17.1% (7)19.4% (6)10.5% (4)26.8% (11)0% (0)
51- 75%36.8% (14)41.5% (17)12.9% (4)31.6% (12)12.2% (5)0% (0)
76 -100%23.7% (9)34.1% (14)0% (0)50.0% (19)19.5% (8)0% (0)
Other*2.6% (1)0% (0)6.4% (2)2.6% (1)0% (0)0% (0)
* staining patterns can't be determined due to loss of tissue.

Of the 2 DFSP cases that were CD34 negative, both demonstrated over 50% Ki67 positivity and were MMP-11 negative as well. Of the 5 VDF cases that were CD34 positive, distinctions from DFSP were supported by strong positive staining of MMP-11 and CD10 and very low expression of Ki67.
Conclusions: Our results demonstrate that VDF has staining patterns comparable to classical DF. MMP-11 and CD10 stains can be useful in the differential diagnosis of VDF and DFSP.
Category: Dermatopathology

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 95, Tuesday Morning

 

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