Metaplastic breast cancer masquerading as a recurrent haematoma: A case report.

An 85-year-old Chinese lady presented with a 5-day history of a painless left breast lump. There was no fever, nipple discharge, or history of trauma. She had a past medical history of atrial fibrillation that was managed with an oral anticoagulant. Mammography demonstrated a dense mass in the upper outer quadrant of the left breast. Ultrasound showed an irregular, heterogeneous 4.7 cm lesion containing debris and cystic spaces with raised peripheral vascularity at the 2 o'clock position, 3 cm from nipple. No internal vascularity was detected. This was managed as a haematoma and rivaroxaban was withheld. Follow-up imaging 3-weeks later showed persistence of the lesion. Bedside needle aspiration yielded haemoserous fluid with immediate reduction in size of the lesion. However, 2 weeks after aspiration, there was recurrence of the 'haematoma'. Multidisciplinary review of the clinical history, examination and imaging was sought, and biopsy of the irregularly thickened areas with vascularity along the periphery of the lesion was recommended. Vacuum-assisted biopsy was performed, and histology returned as metaplastic carcinoma. A recurring 'haematoma' should always prompt a search for a secondary cause, with features such as irregular thickened walls and papillary/nodular components requiring further evaluation with biopsy for histopathological correlation.