• BREAST CANCER
• SARCOMAS
• BREAST PATHOLOGY

According to the recent National Comprehensive Cancer Network guidelines for breast cancer treatment, adjuvant radiation therapy is an important integral component of locoregional treatment of non-invasive and invasive breast carcinomas when lumpectomy is the surgery of choice.1 Despite its benefit in treating cancer, radiotherapy can cause a so-called ‘radiation-induced sarcoma’, a rare iatrogenic malignancy that comprises approximately 3% of all soft tissue sarcomas and is associated with poor outcome. Among radiation-induced sarcomas that occur after radiotherapy for breast carcinoma, angiosarcoma is the most common histological type whereas other types of sarcoma are less frequently encountered.2 We report an unusual case of metachronously occurring spindle cell sarcoma in the right breast and left chest wall of a 38-year-old women who had received radiation for bilateral breast carcinomas.

Chronological details of pathological findings are summarised in table 1. The latest presentation was a 1.1 cm-sized nodule on the left chest wall (post mastectomy) that was excised, showing a tumour within the subcutaneous soft tissue, with cut sections revealing a fleshy grey-white appearance. Microscopically, there were plump spindle cells with moderate to marked nuclear pleomorphism, arranged in long and short fascicles with focal storiform patterns. No residual breast tissue was found. A similar histological appearance was observed in a 2.2 cm-sized lesion discovered 3 years earlier in the contralateral right breast (post-wide excision). Both tumours were mitotically active (at least 20 mitoses per 10 high power fields) with several atypical mitotic figures and apoptotic bodies. Nuclei of the spindle cells were vesicular in appearance with some showing coarse-clumped chromatin, with the right breast spindle cell tumour disclosing more modest nuclear atypia than the latest left chest wall nodule. Cytoplasm was pale eosinophilic with ill-defined borders. Tumour necrosis was not seen. An epithelial component was not identified in either tumour.