Postradiation Cutaneous Angiosarcoma after Treatment of Breast Carcinoma Is Characterized by c-MYC Amplification in Contrast to Atypical Vascular Lesions after Radiotherapy and Control Cases. Clinicopathologic, Immunohistochemical and Molecular Analysis of 61 Cases.
Thomas Mentzel, Hans-Ulrich Schildhaus, Gabriele Palmedo, Reinhard Buttner, Heinz Kutzner. Dermatopathology Bodensee, Friedrichshafen, Germany; University of Bonn, Germany
Background: Postradiation cutaneous vascular lesions after treatment of breast carcinoma comprise a heterogeneous group of benign, atypical, and malignant lesions and are best regarded as points along a morphologic spectrum. There is a significant clinical, histological, and immunohistochemical overlap between atypical vascular lesions and cutaneous angiosarcomas and exact prognostication of single cases remains very problematic. We analysed a series of cutaneous angiosarcomas after treatment of breast cancer in comparison to control cases and cases of atypical vascular lesions with special emphasis of the expression and amplification of c-MYC.
Design: We examined cases from our routine and referral files and evaluated histologic, immunohistochemical and molecular features. The 61 cases were divided into control cases (4), cases in which a slight vascular proliferation was seen after radiotherapy of breast cancer (12), cases of atypical vascular lesions after radiotherapy (15), cases of postradiation cutaneous angiosarcomas (22), and cases of angiosarcomas of skin and soft tissues unrelated to radiotherapy (8).
Results: None of the control cases (2 M, 2 F, 20-76 years, hobnail hemangioma, hemangiolymphangioma, postirradiation colitis), of cases showing slight vascular proliferation, dermal fibrosis and inflammation after radiotherapy of breast cancer (12 F, 48-79 years), of cases of atypical vascular lesions after radiotherapy including benign lymphangiomatous papules and atypical vascular proliferations (15 F, 29-81 years), and of cases of angiosarcomas of skin and soft tissues unrelated to radiotherapy (3 M, 5 F, 25-92 years) showed an amplification of c-MYC by FISH-analysis. In striking contrast, in all cases of postradiation cutaneous angiosarcomas (22 F, 46-95 years) a c-MYC amplification was found by FISH-analysis in a variable number of counted nuclei. Immunohistochemically, a strong positive nuclear staining for c-myc and prox-1 was seen in cases of postradiation cutaneous angiosarcoma, whereas control cases, and cases of atypical vascular proliferation after radiotherapy were negative for c-myc, and stained only focally positive for prox-1.
Conclusions: The presence of c-MYC amplification represents an important additional diagnostic tool in the distinction of postradiation cutaneous angiosarcomas from atypical vascular lesions after radiotherapy.
Monday, February 28, 2011 1:00 PM
Platform Session: Section F, Monday Afternoon