PMC

Transmission electron micrograph of rhabdomyoma. Numerous mitochondria and glycogen inclusions (asterisk) are seen (a) among the myofibrils (arrows) (b). Bars: A = 2,5 µm; B = 1 µm.

Clinical appearance of the lesion. Extensive soft tissue mass in the left floor of the mouth (a). Gross specimen revealed lobules of tumor tissue (b). Clinical aspect after surgery (c).

Histopathology and immunohistochemistry of the lesion. Microscopic examination showing large polygonal cells with eosinophilic and vacuolated cytoplasm (hematoxylin and eosin stain; original magnification: 20x) (a), Masson's trichrome staining demonstrating red round, oval, and polygonal cells (original magnification 20x) (b), immunohistochemical stain showing strong positivity against muscle-specific actin (c), and desmin antigens (d) (original magnification, 40x).