title: Differential expression of HMGA1 and HMGA2 in dermatofibroma and dermatofibrosarcoma protuberans: potential diagnostic applications, and comparison with histologic findings, CD34, and factor XIIIa immunoreactivity.
abstract: The histologic distinction of dermatofibrosarcoma protuberans (DFSP) and dermatofibroma (DF) may be difficult, especially in the case of DF extending into the subcutaneous fat (deep DF). CD34 and Factor XIIIa staining is commonly used in separating DF from DFSP, but is not always helpful. HMGA1 and HMGA2 genes, members of the high mobility group protein family genes, encode proteins that act as architectural transcription factors and are frequently dysregulated in a variety of benign or locally aggressive mesenchymal tumors. In this study, we evaluated the immunoreactivity of HMGA1 and HMGA2 in a series of DF and DFSP to determine the possible utility for these markers in the differential diagnosis of these two entities. Immunohistochemical stains were performed on paraffin-embedded tissues from 22 cases of DF, including 14 cases of deep DF and 14 cases of DFSP, using antibodies against HMGA1 and HMGA2. CD34 and Factor XIIIa immunoreactivity was also evaluated in these lesions and compared with the results of HMGA immunostaining. Immunopositivity for both HMGA1 and HMGA2 was seen in 21of 22 (96%) DFs, but in only 3 (21%) and 1 (7%) of 14 DFSPs, respectively. While 100% of DFSP stained for CD34, 36% of DF also labeled for CD34. The immunoreactivity of HMGA1 and HMGA2 in DF was generally strong and diffuse, in contrast to weak and focal staining seen in DFSP. The proportion of cases with positive immunoreactivity for both markers was significantly higher in DF and in deep DF than in DFSP (P < 0.001). We conclude that HMGA1 and HMGA2 expression can be used to distinguish DF from DFSP with a degree of accuracy that is fully equivalent to that of Factor XIIIa and CD34.
authors.affiliation: Department of Pathology, Yale University School of Medicine, New Haven, CT 06504-8900, USA. ning_li@comcast.net
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Jennifer
authors.initials: J
authors.lastname: McNiff
authors.forename: Pei
authors.initials: P
authors.lastname: Hui
authors.forename: Guidalberto
authors.initials: G
authors.lastname: Manfioletti
authors.forename: Giovanni
authors.initials: G
authors.lastname: Tallini
mesh_terms: D000328:Adult; D018952:Antigens, CD34 / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism; D018223:Dermatofibrosarcoma / Q000378:metabolism* / Q000473:pathology; D003937:Diagnosis, Differential; D026122:Factor XIIIa / Q000378:metabolism*; D005260:Female; D024003:HMGA Proteins / Q000378:metabolism*; D025741:HMGA1a Protein / Q000378:metabolism; D025743:HMGA2 Protein / Q000378:metabolism; D018219:Histiocytoma, Benign Fibrous / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology
chemical_list: D018952:Antigens, CD34; D014408:Biomarkers, Tumor; D024003:HMGA Proteins; D025743:HMGA2 Protein; D025741:HMGA1a Protein; D026122:Factor XIIIa