Leiomyosarcoma with osteoclast-like (LMS-OGC) giant cells the breast: A report of a rare case.

Leiomyosarcoma with osteoclast-like giant cells (LMS-OGC) has seldom been reported clinically. LMS-OGC of the breast is extremely rare according to the literature. Here, we report a case of LMS-OGC leiomyosarcoma with osteoclast-like giant cells of the breast. A 51-year-old female patient presented with a breast mass which was treated surgically and the pathological examination of the tumor indicated LMS-OGC. Microscopically, the tumor was composed of spindle cells arranged in bundles or spokes with giant tumor cells and mitosis. Eosinophilic cytoplasm and morphologically benign osteoclast-like cells were mixed together. Immunohistochemistry examination revealed SMA and desmin were positive with a Ki-67 proliferation index of 40%. However, CK (AE1/AE3), E-cadherin, ER, PR, CD34, S-100 and CD10 were negatively expressed in the tumor tissue. LMS-OGC is a soft tissue malignant tumor which develops extremely rarely in the breast. It should be differentiated and diagnosed according to the history, histological characteristics and immunohistochemical staining.