Angiosarcoma: a difficult diagnosis

A 28-year-old nulliparous lady was referred to the breast clinic with a 5-month history of persistent, cyclical, left-sided mastalgia. She was otherwise fit and healthy with no previous breast or nipple complaints. She was originally from Hong Kong with no family history of breast cancer. She was not prescribed any medications and was a non-smoker. On examination, tender nodularity was elicited below the left nipple. There were no other abnormalities. Ultrasound scan (USS) of this area demonstrated an irregular area of mixed echogenicity, probably in keeping with fibroadenosis (Figure 1). Mammography performed subsequently demonstrated dense fibro-glandular tissue with no mass (Figure 2). Fine needle aspiration (FNA) of the area demonstrated fibro-fatty tissue with very scanty ductal cells. This was unsatisfactory for diagnosis (C1 cytology). A clinical core biopsy was desired but not completed on this consultation at the patient's request. At subsequent review, a clinical core biopsy was performed in view of persistent nodularity. The core biopsy demonstrated a well-differentiated, vasoformative endothelial tumour, which appeared haemangioma–like, involving the surrounding fat and fibrous tissue, between breast ducts. In areas the lesion appeared to have an infiltrative pattern with vessels dissecting the septal fibrous tissue present. The cells showed a high degree of vascular endothelial differentiation but had enlarged hyperchromatic and mildly pleomorphic nuclei. Although mitotic figures were not identified, the appearances were suggestive of well-differentiated, grade-1 angiosarcoma (Figure 3). An expert second opinion was sought and concurred with this interpretation. There was positive immunohistochemical staining for CD34, CD31, and for factor VIII. MIB-1 proliferation was low. This is a polyclonal antibody used in paraffin embedded tissue against the Ki-67 antigen and is an indicator of cell proliferation. A magnetic resonance image (MRI) scan was recommended but was unhelpful, demonstrating no abnormality. An USS guided localisation-biopsy was performed without complication. Macroscopically the tissue was haemorrhagic. Histology confirmed the presence of a 2.2 cm, well-differentiated, invasive angiosarcoma extending to three of the resection margins. Following counselling, she subsequently had a left mastectomy with immediate expandable implant reconstruction. This was completed without complication. Macroscopic analysis of the resected mastectomy specimen demonstrated an ill-defined residual haemorrhagic lesion measuring 4 cm × 4 cm × 2 cm. Histology confirmed the presence of residual angiosarcoma, up to intermediate-grade malignancy. Unfortunately, the inferior-superficial margin was still not clear of disease and she required re-excision to achieve a clear margin. The breast implant was not disturbed and remained in-situ during the re-excision. She is awaiting radiotherapy to the operative site, which has had to be delayed, as she is now seven weeks pregnant. She is otherwise well.