J Breast Cancer.  2011 Jun;14(2):160-164. 10.4048/jbc.2011.14.2.160.

Primary Acinic Cell Carcinoma of the Breast: A Case Report with an Immunohistochemical and Ultrastructural Studies

• Chang ED
• Lee EJ
• Lee AW
• Kim JS
• Kang CS

• KMID: 2286518
• DOI: http://doi.org/10.4048/jbc.2011.14.2.160

Abstract

Acinic cell carcinoma (ACC) of the breast is extremely rare and is characterized by widespread acinar cell-like differentiation. We report of a 39-year-old woman presented with a palpable breast mass with significant morphological, immunohistochemical and ultrastructural findings. Histologically, ACC showed a diffuse glandular infiltrative pattern, with small acinar or glandular structures mixed with solid nests. Neoplastic cells were monotonous proliferation of cells with a granular or clear cytoplasm, resembling acinar cells of the salivary glands or Paneth cells. Both glandular and solid tumor cell populations were strongly positive for lysozyme and alpha-1-antitrypsin.

Keyword

Acinic cell carcinoma; Breast neoplasms; Electron microscopy; Immunohistochemistry

MeSH Terms

Acinar Cells
Adult
Breast
Breast Neoplasms
Carcinoma, Acinar Cell
Cytoplasm
Female
Humans
Immunohistochemistry
Microscopy, Electron
Muramidase
Paneth Cells
Salivary Glands
Muramidase

Figure

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  Figure 1 The tumor was a 5.5×3.0 cm, ill defined mass, with a gray brown rubbery consistency and a slightly lobulated appearance.

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  Figure 2 Tumor cells growing in diffuse infiltrative patterns with small acinar or glandular structures and large solid nests in a fibro-fatty stroma and a normal mammary parenchyma (H&E stain, ×40).

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  Figure 3 Tumor cells were characterized by monotonous round cells with a finely granular, weakly eosinophilic, or clearly vacuolated cytoplasm and resembled acinic cells of the salivary glands (H&E stain, ×200).

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  Figure 4 Tumor cells showing dark eosinophilic coarse granules, resembling Paneth cells. Nuclei were irregular, and some intranuclear inclusions were noted (H&E stain, ×200).

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  Figure 5 Large solid nests of tumor cells revealed central comedo-like necrosis, reminiscent of ductal carcinoma in situ (H&E stain, ×100).

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  Figure 6 Immunohistochemical staining shows (A) strong immunoreactivity to lysozyme, (B) complete circumferential intense staining for E cadherin, (C) focal cytoplasmic reaction to S-100 protein, and (D) weak positivity for CK 7 in the luminal membrane of tumor cells and a strong positive reaction in normal ducts (A-C, ×100; D, ×200).

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  Figure 7 Electron microscopy revealed numerous variably sized electron dense granules in the cytoplasm, that were consistent with acinar cell granules, and a prominent, rough endoplasmic reticulum (×7,000).

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