A spontaneous myoepithelial carcinoma in the mammary gland of an aged female ICR (CD-1) mouse

作者：Ito Tsuyoshi^*; Yoshida Toshinori^*; Soma Katsumi; Katoh Yoshitaka; Shimada Yuko; Ohnuma Koyama Aya; Takahashi Naofumi; Okazaki Yoshimasa; Shiga Atsushi; Kuwahara Maki; Harada Takanori

来源：Journal of Toxicologic Pathology, 2017, 30(3): 245-250.

DOI：10.1293/tox.2016-0080

• ICR mouse
• mammary gland tumors
• myoepithelial carcinoma
• myoepithelial cells
• spontaneous tumor

We report a female Crlj:CD1(ICR) mouse with a spontaneous mammary gland tumor composed of biphasic tumor cells, i.e., epithelioid and spindle-shaped myoepithelial cells. Macroscopically, a subcutaneous mass, approximately 3 cm in diameter was found in the lumbodorsal region. Histopathologically, the epithelioid cells proliferated in an alveolar or nest-like growth pattern, occasionally forming glandular-like structures. On the other hand, the spindle-shaped cells proliferated in a sarcomatous pattern. Normal mammary gland was observed in the vicinity of the tumor. Both types of tumor cells showed immunoreactivity for cytokeratin (wide spectrum screening), vimentin, S100, and p63. In addition, the epithelioid cells and spindle-shaped cells were immunopositive for glial fibrillary acidic protein and smooth muscle actin, respectively. Moderate atypia, high proliferative activity, massive necrosis, and partial infiltration to the surrounding tissues were also observed. We made a diagnosis of myoepithelial carcinoma, which is extremely rare in ICR mice.

• 出版日期2017