CASE REPORT Angiosarcoma Developing in a Breast After Conservation Treatment for Breast Cancer Robert G. Parker, MD,* Sanford H. Barsky, MD,† and Robert Bennion, MD‡ Key Words: angiosaroma, breast cancer, breast conservation (Am J Clin Oncol 2003;26: 486 – 488) M ost breast cancers related to ionizing radiations are invasive ductal adenocarcinomas. After irradiation of the breast as part of conservation treatment, it may not be possible to delineate radiation-induced from recurrent cancer because of similar histologies. This is a report of a patient in whom a distinct angiosarcoma developed after irradiation of the breast. CASE REPORT In February 1997, this 80-year-old woman had conser- vation treatment for a moderately well-differentiated infiltrat- ing ductal carcinoma in the left breast. This primary tumor in the upper outer quadrant of the left breast was 1.8 cm in largest dimension. The surgical margins after excision were tumor free, although there was a noncomedo ductal carci- noma in situ component within 0.1 mm of one margin. An axillary dissection was not done. The breast was irradiated through opposed tangential fields to a calculated dose of 5,040 cGy at the 90% isodose line using 6-MV photons. A boost of 1,600 cGy was delivered to the 90% isodose line using a 10-MeV electron beam. The left supraclavicular fossa and axilla were irradiated with photons to a dose of 5,040 cGy calculated at a depth of 3.0 cm from the anterior surface. The overall treatment time was 49 days. The patient tolerated the treatment without difficulty with only a mild, diffuse skin erythema. She was started and continued on tamoxifen 20 mg daily. Since treatment, the left breast was visibly and palpably normal until August 2001 when a purplish-red discoloration with serpiginous margins measuring 8.0 cm in greatest di- mension was noted surrounding the nipple. There were no signs of inflammation. The breast was palpably normal. On October 31, 2001, a biopsy of the skin was interpreted as low grade angiosarcoma. On a mammogram dated November 29, 2001, the findings were “benign” without change from pre- vious mammograms. No metastases were visible on a com- puted tomography examination of the chest. There has been no edema of the left upper limb. On February 19, 2002, a left mastectomy was done. Gross pathologic analysis of the mastectomy specimen re- vealed violaceous discoloration of the skin around the nipple. There was no ulceration or dominant mass. Microscopic pathologic analysis revealed a proliferation of mature and slightly immature vascular channels lined by endothelial cells in the papillary dermis (Fig. 1A) and reticular dermis (Fig. 1B). The vascular channels were angulated, were not con- fined to lobules, and infiltrated the adjacent dermal layers. In some areas, the vascular proliferation consisted of “back-to- back” vascular structures with diminutive lumina. The vas- cular proliferation was most dense directly under the epider- mis and became sparser with increasing depth from the skin surface. The vascular proliferation was confined to the dermis and did not penetrate the underlying subcutaneous tissue or the underlying breast. Immunocytochemical analysis with antibodies to CD31 and factor VIII-related antigen (Von Willebrand factor) revealed that the endothelial cells lining the proliferating vascular channels exhibited intense immu- noreactivity for both endothelial antigens (Fig. 1C). All of these features supported a diagnosis of low grade angiosar- coma of the skin of the breast. DISCUSSION Primary angiosarcomas arising in the breast account for less than 0.04% of primary breast cancers. 1 Secondary an- giosarcomas have been reported after mastectomy with or without radiation therapy to the chest wall and regional lymph nodes. Steward and Treves 2 reported on six patients who developed elephantiasis chirurgica 6 to 24 years after mastectomy. The tumors did not initially appear in the oper- ative field or skin of the axilla, but in the skin of the upper limb that became edematous immediately after mastectomy. From the *Departments of Radiation Oncology, †Pathology, and ‡Surgery, UCLA Medical Center, Los Angeles, California, U.S.A. Address correspondence and reprint requests to . Copyright © 2003 by Lippincott Williams & Wilkins 0277-3732/03/2605-0486 DOI: 10.1097/01.coc.0000037738.84777.E5 American Journal of Clinical Oncology • Volume 26, Number 5, October 2003 486