Adenomyoepithelioma of the Breast. A Case Report

Benign adenomyoepitelioma of the breast: Presentation of two rare cases and review of literature

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Adenomyoepithelioma of the breast is a rare benign breast neoplasm.

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The rarity of this histological type of benign breast tumor and the finding of two cases in a short period makes this case report unique.

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Although benign, adenomyoepithelioma has a potential for local recurrence; therefore, wide excision is recommended.

Introduction

Adenomyoepithelioma of the breast is a rare benign breast neoplasm with a particular behaviour.

Presentation of cases

We report two cases of adenomyoepithelioma of the breast in two old female patients, diagnosed over a period of 5 years. The clinical presentation, the radiological and the histopathologic findings are discussed.

Discussion

Adenomyoepithelioma of the breast is characterized by the proliferation of both epithelial and myoepithelial cells belonging to the breast lobules and ducts. The imaging features are not pathognomonic and FNAB is usually not diagnostic. The morphologic appearance of this tumor varies, and it has to be considered in the differential diagnosis with other breast tumors. Although benign, adenomyoepithelioma has a potential for local recurrence, and malignant transformation is possible; therefore, wide excision is recommended to lower the recurrence rate.

Conclusion

The rarity of this histological type and the finding of two cases in a relatively short period makes this case report unique.

Combined Epithelial-Myoepithelial Lesions of the Breast

Epithelial-myoepithelial proliferations of the breast are a heterogeneous poorly defined group of lesions characterized morphologically by dual differentiation into ductal (luminal) and myoepithelial cells. They include neoplastic and non-neoplastic entities that have overlapping morphologic features that may give rise to diagnostic difficulty. Many of these entities are low grade or of uncertain malignant potential but the biology of some of these rare lesions remains to be elucidated. This article discusses the differential diagnosis of epithelial-myoepithelial lesions of the breast and highlights the morphologic features of some of these entities.

Adenomyoepithelioma of the breast: a review stressing its propensity for malignant transformation

This review describes the classification, clinical presentation, pathological features and clinical behaviour of adenomyoepithelioma (AME) of the breast. It is based on an extensive review of the literature and study of a collection of cases built up over a 17-year period at the British Columbia Cancer Agency. The diversity of the morphology encountered in both benign and malignant AME is described. The behaviour of malignant AME seems to be related to the grade of the malignant component.

Comparative genomic hybridization analysis of myoepithelial carcinoma of the breast

Although there seems to be a common stem cell for the two epithelial cell types in the breast, the vast majority of breast cancers exhibit a luminal phenotype. Pure myoepithelial carcinomas are rare. We report our findings of genetic alterations in these tumors. We have analyzed 10 cases of pure myoepithelial cell carcinomas using laser capture microdissection and comparative genomic hybridization. The mean number of changes was 2.1 (range 0-4), compared with a mean of 8.6 (range 3.6-13.8) in unselected ductal carcinomas. Common alterations included loss at 16q (3/10 cases), 17p (3/10), 11q (2/10), and 16p (2/10), regions also commonly deleted in ductal carcinomas. The single case in which both pure myoepithelial carcinoma and invasive ductal carcinoma was present showed 2 alterations in the myoepithelial tumor (losses at 17p and 17q), whereas the invasive ductal component showed 15 alterations (5 gains and 9 losses), including loss at 17p. The sharing of 17p loss in myoepithelial and ductal carcinoma is consistent with a common stem cell model in the breast. The relatively few genetic alterations in otherwise aggressive neoplasms suggests that myoepithelial tumors may be a good model for the delineation of genes important in breast tumorigenesis.

Adenomyoepithelioma of the Breast: A Case Reprot and a Review of Literature

A 74-year-old woman complained of a small nodule in the outer lower quadrant of her left breast. On physical examination, a 0.9 x 0.8 cm, round-shaped and firmly elastic nodule was palpated. Excisional biopsy was performed. Histologically, the tumor was separated into, with a bicellular pattern, containing both numerous glandular structures and numerous spindle-shaped cells. Immunohistochemical staining for EMA and cytokeratin showed strongly positive immunoreactivity for epithelial cells. Staining for &aipha;-SMA showed strongly positive immunoreactivity for myoepithelial components. Staining for keratin and S-100 protein showed weakly positive immunoreactivity for myoepithelial cells. Microscopically, the tumor was diagnosed as adenomyoepithelioma of the breast. Immunohistochemical examination is needed to distinguish epithelial cell proliferation from myoepithelial cell proliferation. Immunohistochemical examination using antibodies against EMA, alpha-SMA, Keratin, cytokeratin and S-100 protein, is indispensable.

Adenomyoepithelioma of the breast: report of a case initially examined by fine-needle aspiration

This report describes the morphologic features of an adenomyoepithelioma of the breast that was first examined by fine-needle aspiration. On retrospective review of the cytology, the stromal elements of this adenomyoepithelioma showed extensive metachromasia on Diff-Quik stain, had elongated nuclei, and on Papanicolaou stain showed elongated, pale, wispy cytoplasm. Clusters of stromal cells were usually intimately associated with epithelial elements. While the main differential consideration, cystosarcoma phylloides, can show similar features, it may be possible to distinguish the two lesions in some instances.