A 41-year-old woman presents with a palpable mass in her left breast. A lumpectomy is performed.
Correct Answer: B. Pleomorphic adenoma
Pleomorphic adenomas of the breast are rare primary tumors. Just like their counterparts in the salivary glands, these tumors show similar histological and immunohistochemical features, which consist of a proliferation of myoepithelial cell cells embedded in a loose chondromyxoid background. The presence of mature cartilaginous component is not as common as it is when the tumors appear in the salivary glands. Complete surgical resection is curative in these patients.