Metaplastic breast carcinoma is a very infrequent type of malignancy (<1% of invasive breast tumors), of poor prognosis and of high histological grade. It is due to a metaplasia of the breast glandular epithelium. There are several types, among which squamous cell carcinoma is the most frequent. The age of presentation is usually in women older than 50 years who report a fast growing tumor. Radiologically they are usually well circumscribed lesions, and if they are of a large volume they can be complicated, with ulceration or fixation to the skin or even to the chest wall. They have a worse prognosis than patients with infiltrating ductal or lobular carcinoma, with an incidence of metastatic disease between 5-30%. We present the case of a 50 years old woman with a palpable mass in the left breast, ulcerated. We show the characteristics of this entity in the different imaging techniques. Finally, an ultrasound biopsy confirmed the diagnosis of metaplastic breast carcinoma.A 50-year-old woman was addressed to the Gynecology department for palpable mass in the left breast. Physical examination shows a mass of approximately 10 cm that affects the entire breast, with areas of ulceration (Figure 1). Figure 1: Ulcerated mass in left breast.