Breast malignant, males, children - Acinic cell carcinoma

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Breast malignant, males, children

Carcinoma subtypes

Acinic cell carcinoma

Reviewer: Monika Roychowdhury, M.D. (see Reviewers page)
Revised: 13 November 2012, last major update March 2012
Copyright: (c) 2001-2012, PathologyOutlines.com, Inc.

General
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● Identical to salivary gland counterpart, has serous differentiation
● These carcinomas show diffuse infiltrative growth patterns of small glandular structures and are composed of cells with a coarse granular or clear cytoplasm resembling acinar cells of the salivary glands or Paneth cells
● See also Salivary Glands chapter
● Although similar in some respects to secretory carcinoma (Histopathology 2002;40:223),it lacks its characteristic ETV6 gene rearrangement (Histopathology 2008;52:840)

Epidemiology
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● Uncommon in breast, < 20 cases reported

Case reports
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● 39 year old woman (J Breast Cancer 2011;14:160)
● 42 year old woman (Virchows Arch 1996;429:69)
● 49 year old woman with death due to disease (J Clin Pathol 2002;55:545)
● Japanese woman (Pathol Int 2007;57:43)

Clinical description
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● In salivary glands, may undergo high grade transformation (Am J Surg Pathol 2009;33:1137)
● In parotid gland, poorer prognosis if high mitotic activity and necrosis (Cancer 2009;115:2128)
● Clinically low-grade malignant tumor even if unfavorable prognostic parameters such as high mitotic activity and steroid hormone receptor negativity (Histopathology 2004;45:645)

Gross description
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● Often well circumscribed but may be infiltrative
● Gray-pink and hemorrhagic cut surface
● 2-5 cm

Gross images
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5.5 cm ill defined mass

Micro description
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● Monotonous proliferation of cells with abundant finely granular, weakly eosinophilic or clear vacuolated cytoplasm, central round nuclei and prominent nucleoli, resembling acinic cells of salivary gland (J Clin Pathol 2003;56:497)
● Cytoplasmic dark eosinophilic coarse granules (resembling Paneth cells) can be seen
● Often clear cells
● May have microglandular pattern (Virchows Arch 2000;437:74)
● Up to 15 mitotic figures/10 HPF
● May be mixed with ductal carcinoma-like cells (Am Surg 2002;68:993)

Micro images
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Various images

Tumor cells have prominent cytoplasmic granularity

Post-chemotherapy tumor has cells with clear vacuolated cytoplasm

Fig A/B

Salivary gland tumors:

Papillary fronds with hobnail cells and vacuolated cells

Microcystic and solid patterns in tumors from father and daughter

Tumor with clear cells

Dedifferentiated tumor

Various micro images

Fig 1: Dedifferentiated parotid tumor with some classic areas
Fig 2: Mitotic figures and necrosis
Fig 3: Differentiated areas with basophilic cytoplasm and vesicular nuclei
Fig 4: PAS+ diastase resistant granules

Various images

Cytology images
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Salivary gland: acinar-like cells with larger nuclei, no ducts, no fibrofatty stroma, no “bunch of grapes” architecture

Positive stains
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● CK7 (may be focal or weak), amylase
● Granules are PAS+ diastase resistant
● E-cadherin
● Also lysozyme, EMA, myoepithelial markers (including S100), alpha-1-antitrypsin

Negative stains
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● ER, PR, HER2, CK20; also GCDFP-15, CD68, NSE, MUC2, SMA

EM description
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● Multiple round, electron dense, cytoplasmic secretory granules

EM images
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Electron dense granules

Clear cells in post-chemotherapy patient have dilated endoplasmic reticulum

Variably sized electron dense granules in the cytoplasm

Differential diagnosis
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● Lactating lobule: lysozyme+, benign morphology
● Microglandular adenosis: intact basal lamina

End of Breast malignant, males, children > Carcinoma subtypes > Acinic cell carcinoma

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