A Unique Case of Muscle-Invasive Metastatic Breast Cancer Mimicking Myositis

Figure 2

(a) Malignant cells (arrows) infiltrating through skeletal muscle and fibroconnective tissue (hematoxylin-eosin, original magnification ×100). (b) A higher power view shows malignant cells infiltrating singly or in small clusters through muscle and fibroconnective tissue. No tubule formation is identified, which is typical of invasive lobular breast carcinoma (hematoxylin-eosin, original magnification ×200). (c) Malignant cells alone and in single file strongly immunoreactive for GATA-3, a luminal marker for breast epithelium (original magnification ×200). (d) Malignant cells showing strong immunoreactivity for mammaglobin, another marker specific for breast carcinoma (original magnification ×400).

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