A case of adenomyoepithelioma with myoepithelial carcinoma of the breast

Abstract

Adenomyoepithelioma with myoepithelial carcinoma of the breast is rare and diagnosed with histology and immunohistochemistry. We present a case of malignant transformation over 10 years, with ultrasonographic findings, highlighting the importance of an early excisional biopsy. Conservative surgery and radiation therapy were performed. There was no recurrence for 2 years.

Keywords: adenomyoepithelioma; breast cancer; myoepithelial carcinoma.

Figure 1

Ultrasonography of a lump in the left breast. Ultrasonography (A) at the initial visit shows a flat and well‐defined hypoechoic lesion measuring 0.8 cm (BI‐RADS category 2), (B) 8 y after the initial visit shows a homogenous hypoechoic lesion measuring 1.5 cm with posterior acoustic shadow, slightly taller than wide ratio and lobulation (BI‐RADS category 5), (C) 9 y after the initial visit shows a more lobulated hypoechoic lesion measuring 1.7 cm (BI‐RADS category 5), and (D) 10 y after the initial visit shows a solid irregular lobulated heterogeneous hypoechoic lesion with a partially unclear border measuring 2.5 cm (BI‐RADS category 5)

Figure 2

Preoperative left mammography. Shown is a high‐density, well‐demarcated lesion with round macrocalcification and no spicules in the outer, middle area of the left breast (white arrow; BI‐RADS category 3). CC, craniocaudal view; MLO, mediolateral oblique view

Figure 3

Characteristics of the tumor. A, Macroscopically, the tumor is solid and grayish with focal yellowish parts and cystic degeneration. B, Microscopically, the right side of the figure shows the AME component, while the left side shows the myoepithelial carcinoma component. No separation is seen between the two components. Black asterisk indicates necrosis (×2). C, The AME component shows biphasic proliferation of both ductal epithelium and myoepithelium (×20), and D, the myoepithelial carcinoma component shows monophasic proliferation. The cytoplasm is pale, and the nuclei are pleomorphic and heterogeneous in size. Black arrows indicate mitosis (×40) (B‐D: hematoxylin and eosin stain)

Figure 4

Immunohistochemical analysis. Myoepithelial cells of the AME (right side) and myoepithelial carcinoma (left side) components are positive for (A) HHF35 (×20), (B) α‐SMA (×20), (C) calponin (×20), (D) S‐100 (×20), (E) CD10 (×20), and (F) p63 (×20)