Fig. 4

Histopathology results. Comparison of pathological examination results between platysma and affected sternocleidomastoid muscle. The platysma muscle is seen to be red during the operation (a). Hematoxylin and eosin (HE) staining shows only occasional adipocytes (b, c), and Masson staining shows only mild fibrosis (d, e). In contrast, the affected SCM has a white color (f). HE staining shows abnormal infiltration by adipocytes (green arrow; g, h). Masson staining shows that the fibrosis ratio is higher in the sternocleidomastoid muscle than in the platysma (i, j)