Possible secondary angiosarcoma following subcutaneous mastectomy with primary reconstruction without subsequent radiotherapy: A case report and literature review

• Secondary angiosarcoma with c-Myc expression in breast cancer patients following surgery can rarely occur despite no subsequent radiation. • Surgical trauma may possibly be associated with the release of components of growth for angiosarcoma. • Post-surgical complications localized in the breast should not be taken lightly and thus should be monitored. Angiosarcoma is a rare aggressive tumor of the endothelial cells, that in its secondary form can be seen in breast cancer patients 5-10 years following radiation therapy or radical mastectomy with chronic lymphedema. In this article, we report a rare case of a breast cancer patient developing possible secondary angiosarcoma following surgery while having received no subsequent radiation therapy. A 66-year-old female presented in 2016 with invasive ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS) in her right breast. She was treated with a subcutaneous mastectomy and primary reconstruction using a DIEP-flap (deep inferior epigastric perforator flap). She received postoperative adjuvant chemotherapy combined with HER2 targeted therapy, but no radiation therapy. In 2023, the patient presented with yellowish marks on the reconstructed breast and a history of trauma to the right side of her body, suggestive of hematoma. Clinical mammography and fine needle aspiration showed only reactive changes. In the following months the cutaneous changes worsened with ulceration, discoloration, and bleeding in the reconstructed breast. A core needle biopsy was taken and angiosarcoma with high malignancy grade was found. Microscopically, the tumor was composed of malignant mesenchymal spindle cells in a hypercellular and slit-like pattern with numerous mitotic figures and nuclear pleomorphism with oval and enlarged nucleoli. Immunohistochemical stain was strongly positive of CD34, CD31 and, remarkably, c-Myc. There was no expression of D240, cytokeratin or S-100. The case highlights that angiosarcoma cannot be excluded in patients following extensive surgery and that we must be aware of this risk in the future.