Mammary-type myofibroblastoma with infarction and atypical mitosis-a potential diagnostic pitfall: A case report

Figure 3 Histopathological features of the tumor. A: The mass had a definite capsule; B: It was composed of short spindle to oval-shaped cells, and admixed with varying thick bundles of collagen and variable numbers of adipocytes. The cells had eosinophilic cytoplasm with indistinct cell borders and elongated nuclei with fine chromatin; C: Hyaline degeneration was visible within the tumor; D: Mucoid degeneration was visible within the tumor; E: Bizarre cells and atypic cells were unequally distributed throughout the tumor; F: Mitosis was found in the tumor cells; G: Atypical mitosis was found in the tumor cells; H: Infarction and nuclear debris were also seen inside the tumor; I and J: Smooth muscles had been infiltrated by the tumor cells; K and L: Skeletal muscles had been infiltrated by the tumor cells. Images I and K show local magnification of the black and blue boxes, respectively, in Figure A. Image J shows the infiltrated smooth muscle, which was positive for smooth muscle actin. Image L displays the invaded skeletal muscle, which was positive for desmin on immunohistochemical staining.