Acinic cell carcinoma of the breast arising in microglandular adenosis

Abstract

Acinic cell carcinoma is a rare breast tumour belonging to salivary gland-like tumours of the breast. They are "triple-negative" breast cancers even if their biological behaviour seems to be more favourable. Herein we present an acinic cell carcinoma arising on a background of typical and atypical microglandular adenosis in a 58-year-old woman, along with a review of the literature.

Figure 1

Craniocaudal (a) and oblique (b) view of mammography imaging showing radiopacity and thickening with microcalcifications (arrow). (c) Echographic study of the lesion showing, in the same area of (a) and (b), some nodular features. (d) Gross feature of the surgical specimen showing irregular whitish nodule of about 3 cm of diameter with a 8 mm small pseudocystic area. (e) Panoramic view showing nodular and pseudocystic arrangement of tumor (H/E, 100x). (f) Microglandular and microacinar features of tumour cells with small glandular structures arranged back to back and interspersed within fat or fibrous septa (H/E, 100x). (g) High power view of the solid features of the lesion showing high pleomorphic cells, mitotic activity, and necrosis (H/E, 400x). (h) High power view of microglandular structures showing colloid-like secretion in the central lumina and cytoplasmic eosinophilic granules (H/E, 400x). (i) High power view showing colloid-like secretion and cytoplasmic eosinophilic granules after PAS-diastase reaction (H/E, 400x).

Figure 2

(a) Immunohistochemical assay for EMA (200x). (b) Immunohistochemical assay for S-100 (200x). (c) Immunohistochemical assay for α-1-antitrypsin (200x). (d) Immunohistochemical assay for lysozyme (200x). (e) Immunohistochemical assay for amylase (200x). (f) Immunohistochemical assay for progesterone receptor (200x). (g) Panoramic view of the section showing foci of microglandular adenosis at the periphery of the tumour (H/E, 200x). (h) Ultrastructural study showing variable sized electron dense cytoplasmatic granules.