PMC5506483_01
Significant thickening of the sternocleidomastoid muscles (blue arrows). Soft tissue density obliterating numerous fat planes extending into the mediastinum and completely encasing the major vessels and left paraspinal musculature including the left trapezius muscle (red arrow). The very few cases of breast cancer metastatic to the soft tissues predominantly describe focal or mass-like involvement. This diffuse, infiltrating appearance is highly unusual and most characteristic of severe infection/inflammation such as myositis or necrotizing fasciitis.
CRIONM2017-2648296.001.jpg
PMC5506483_01_CRIONM2017-2648296.001.jpg
fig1
There was also moderate narrowing of the supraglottic airway (Figure 1).
(a) Malignant cells (arrows) infiltrating through skeletal muscle and fibroconnective tissue (hematoxylin-eosin, original magnification x100). (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 x200). (c) Malignant cells alone and in single file strongly immunoreactive for GATA-3, a luminal marker for breast epithelium (original magnification x200). (d) Malignant cells showing strong immunoreactivity for mammaglobin, another marker specific for breast carcinoma (original magnification x400).
CRIONM2017-2648296.002.jpg
PMC5506483_01_CRIONM2017-2648296.002.jpg
fig2
TTF-1, CD34, CD30, and PAX-8 (Figure 2). Staining with mammaglobin showed strong positivity within malignant cells. These immunohistochemical findings were most consistent with a breast primary malignancy.