Adenomyoepithelial adenosis associated with breast cancer: a case report and review of the literature
© Maeda et al.; licensee Springer. 2013
Received: 27 January 2013
Accepted: 30 January 2013
Published: 13 February 2013
Adenomyoepithelial adenosis of the breast is an extremely rare type of adenosis. We herein present the case of a 35-year-old woman, who presented with a small painless hard lump and elastic soft induration of 5 cm in diameter in her left breast. Clinical examination and diagnostic workup were suggestive of a breast carcinoma, and a modified radical mastectomy and sentinel node biopsy were performed. Histopathological examination revealed adenomyoepithelial adenosis along with fibrocystic change and small invasive ductal carcinoma, slightly away from the adenosis. The presented case was thought to be initial-stage adenomyoepithelial adenosis and independently developing breast cancer. From a review of five reported cases of adenomyoepithelial adenosis, complete resection of the tumor and coexisting malignant disease may be recommended, owing to the tendency to develop breast cancer or malignant adenomyoepithelioma, or recurrence.
Adenomyoepithelial adenosis is an extremely rare type of adenosis associated with adenomyoepithelioma (Tavassoli & Soares2003; Moinfar2007) and has been shown to exhibit highly proliferative activity in both glandular epithelial and myoepithelial cells. This rare adenosis was considered to be prone to progression to definitive carcinoma (Tsuda et al.1994; Tavassoli1991). In this paper, the case of a 35-year-old woman with breast cancer combined with fibrocystic disease, which was diagnosed as adenomyoepithelial adenosis after mastectomy, is reported. Presenting symptoms, diagnostic evaluation and surgical management are discussed along with a review of the literature.
According to the WHO classification Tumors of the Breast and Female Genital Organs (Tavassoli & Soares2003) but not to the new WHO classification (Schmitt et al.2012), myoepithelial lesions of the breast are classified into myoepitheliosis, adenomyoepithelial adenosis, adenomyoepithelioma and malignant myoepithelioma. Adenomyoepithelial adenosis is an extremely rare type of adenosis associated with adenomyoepithelioma (Tavassoli & Soares2003; Moinfar2007). This adenosis consists of a diffuse proliferation of round or irregular tubular structures lined by a cuboidal to columnal epithelium, which may show apocrine metaplasia. There is a prominent, focally hyperplastic myoepithelial cell layer with strikingly clear cytoplasm. There is no significant nuclear atypia or mitotic activity. In most described cases, ademyoepithelial adenosis is mixed with or surrounds an adenomyoepithelioma (Tavassoli & Soares2003).
In terms of the histological findings of this case, hyperplasia of both glandular epithelial cells and myoepithelial cells that had extremely clear cytoplasm was observed, as shown in Figure 4 compatible with the findings of adenomyoepithelial adenosis as reported by Kiaer et al. (Kiaer et al.1984). On the other hand, the adenomyoepithelial adenosis in this case was mixed with fibrocystic changes such as dilated ducts, duct papillomatosis, duct adenosis, sclerosing adenosis, duct ectasia or apocrine metaplasia, but not with adenomyoepithelioma as previously reported in three cases (Kiaer et al.1984; Eusebi et al.1987; Eusebi et al. 1997). Although the reason for the difference in terms of coexisting disease was unknown, we speculated that this reported case was at the initial stage of such cases because of the very young age, lack of mass formation and the incidental finding after operation. The three previously reported cases were older than 50 years old and had a mass in their breast, suggesting that adenomyoepithelial adenosis may differentiate into benign or malignant adenomyoepithelioma with the passage of several decades (Kiaer et al.1984; Eusebi et al.1987; Eusebi et al.1997. Consistent with our speculation, Erel et al.(Erel et al.2008) reported a patient with adenomyoepithelial adenosis, who was 46 years old and presented with a palpable mass in her right breast. Excisional tumor was diagnosed as fibrocystic change and later, recurrent masses were palpable under the incisional scar. In the re-excisional biopsy specimen, histopathology showed adenomyoepithelial adenosis with neither significant atypia nor mitotic activity without breast cancer or adenomyoepithelioma.
From the viewpoint of Tsuda et al. (Tsuda et al.1994), adenomyoepithelial adenosis was considered to be prone to progression to adenocarcinoma of the breast. This is because they reported a 50-year-old patient with a breast tumor that was present for 20 years and increased in size to 5 cm. After mastectomy, the tumor was diagnosed as adenomyoepithelial adenosis, with highly proliferative activity in both glandular epithelial and myoepithelial cells, and five unmistakable adenocarcinoma foci under 1.0 cm in diameter. In our reported case, the tumor of adenocarcinoma, 0.7 cm in diameter, was slightly separate from the adenomyoepithelial adenosis, which showed neither significant atypia nor mitotic activity and was mixed with fibrocystic disease, suggesting that the occurrence of small breast cancer might be independent of the adenomyoepithelial adenosis.
From a review of five reported cases of adenomyoepithelial adenosis, all five cases had a palpable mass from 1.3 cm to 5 cm in size (Tsuda et al.1994; Kiaer et al.1984; Eusebi et al.1987; Erel et al.2008).
On mammography, one case had a speculated mass with pleomorphic calcification (Erel et al.2008), another case had a mass with irregular margin (Tsuda et al.1994), and a third case (Kiaer et al.1984) had focal asymmetric density. On ultrasonography, two cases showed an irregular hypoechoic mass with posterior acoustic shadow (Tsuda et al.1994; Erel et al.2008). The final diagnostic procedures for adenomyoepithelial adenosis were excisional biopsy in three cases (Kiaer et al.1984; Eusebi et al.1987; Erel et al.2008) and mastectomy in two cases (Tsuda et al.1994; Eusebi et al.1987), in one of whom aspiration cytology was considered false positive for carcinoma (Eusebi et al.1987). Our presented case showed induration of 5.5 cm in diameter and focal asymmetric density with microcalcification on mammography and a restricted hypoechoic area with small simple cysts on sonography; it was diagnosed after mastectomy. From these reported cases, preoperative diagnosis of adenomyoepithelial adenosis was thought to be difficult due to the lack of a specific finding on imaging or false-positive aspiration cytology. Core needle biopsy such as vacuum-assisted biopsy may be suitable (Yahara et al.2008), although this reported case failed to show adenosis, owing to combination with fibrocystic disease, using a 16-gauge needle.
Although it is difficult to reach a conclusion concerning the degree of malignancy, extirpation of the tumor may be recommended owing to the tendency to develop breast cancer or malignant adenomyoepithelioma (Tsuda et al.1994; Kiaer et al.1984), if the preoperative diagnosis of adenomyoepithelial adenosis is performed using needle biopsy. As two cases recurred after excisional biopsy (Kiaer et al.1984; Erel et al.2008), re-excision may be recommended in cases of suspected inadequate margin, like adenomyoepithelioma (Nadelman et al.2006). The best predictors of recurrence are initial incomplete or close excision margins. Therefore, correct preoperative diagnosis of the extent of such disease was thought to be important for surgical planning.
We reported a case of adenomyoepithelial adenosis as an extremely rare type of adenosis, coexisting with invasive ductal carcinoma. Because the presented case was very young with no tumor formation and mixing with fibrocystic change, the case was thought to be an initial stage of adenomyoepithelial adenosis. Owing to the tendency to develop breast cancer or malignant adenomyoepithelioma and recurrence, complete resection of adenomyoepithelial adenosis may be recommended.
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