Gynecomastia-like Changes of the Female Breast: A Clinicopathologic Study of 4 Cases

The term gynecomastia is used to describe male breast enlargement. It is the most common pathologic abnormality of the male breast and has been reported to be present in 30% to 40% of adolescent and adult males.1,2 It is usually a benign condition but may involve other associated underlying diseases. Rarely, carcinoma can arise from gynecomastia.3 Histologically, the lesion has a specific pattern and is characterized as ductal hyperplasia and periductal stromal fibrosis or edema with slight lymphocytic infiltrate.3 

A similar histologic pattern has also been described in the female breast. Due to lack of a specific definition, different authors have named gynecomastia-like changes of the female breast differently. Terms that have been used include gynecomastia-like hyperplasia,3 ,mammary hamartoma or adenolipoma,4 as a pattern within juvenile hypertrophy when occurring in young girls,5 and juvenile fibroadenoma.6 Some authors consider gynecomastia-like changes of the female breast to be a form of ductal hyperplasia.7 

Although gynecomastia-like changes of female breast have been variously described by different authors,3–7 no data are available with respect to incidence, common clinical presentation, mammographic findings, and patients' medical backgrounds. We undertook this study to define this pattern and study its clinical significance. Following our review of the literature on this subject, we believe there are also major histologic differences between previously reported gynecomastia-like changes and male gynecomastia. Lobules were seen in some of the previously described lesions, which is not a feature of male gynecomastia. We developed strict criteria for the diagnosis of gynecomastia-like changes (see “Materials and Methods”). We report 4 cases of gynecomastia-like changes of female breast that fulfill the criteria.

From 1995 to 1999, 2709 breast biopsies and/or surgical excision specimens were processed in our department. These cases were searched by SNOMED classification and were identified by the diagnosis and/or comments of gynecomastia-like change. Among these cases, 9 were noted to have gynecomastia-like changes. Three observers further initially reviewed these 9 cases.

After the initial review, we modified the criteria described by Rosen et al3 as follows:

1. Ductal hyperplasia and periductal stromal fibrosis or edema and slight lymphocytic infiltrate.

2. No terminal duct–lobular units present in area of involvement.

3. The involved area should be greater than 1 scanning field (2 × 10) in an excision specimen. In case of a core biopsy, 1 fragment should be involved entirely and the fragment should be at least 1 cm in length.

4. No associated mammary hamartomatous changes, areas of juvenile hyperplasia, or juvenile fibroadenoma.

Using these criteria we further reviewed and analyzed these cases.

A total of 9 cases were found to have a previous diagnosis of gynecomastia-like changes. After review by 3 pathologists applying the criteria listed in “Materials and Methods,” 5 cases were eliminated. Two excision specimens were eliminated owing to presence of lobules within a scanning low-power field. One excision specimen was eliminated because the consensus diagnosis after further review was juvenile hypertrophy, as described by Tavassoli.5 One other case, although the patient was 52 years old, showed gynecomastia-type change adjacent to areas resembling juvenile hypertrophy. One core biopsy specimen was removed owing to the presence of a mixture of gynecomastia-like changes and other benign alterations within 1 scanning low-power field.

Four of the 9 cases that had a previous diagnosis of gynecomastia-like changes were found to fulfill our criteria. Three were excision biopsies, and 1 was a core biopsy in which the entire fragment demonstrated gynecomastia-type changes and which fulfilled the criteria for core biopsy specimens outlined in the “Materials and Methods.”

Case 1.—A 39-year-old woman had fullness in the upper inner quadrant of her right breast. A palpable mass was felt both by the patient and by her physician. Malignancy was suspected. No mammography or ultrasound examination was performed. A surgical excision biopsy was performed. A tan-pink to tan-yellow, lobulated, irregular mass measuring 3.5 × 2 × 2 cm was obtained. Pathologic examination revealed breast tissue with fibrocystic changes and gynecomastia-like changes occupying 1 low-scanning-power field (Figures 1 and 2).

Case 2.—A 28-year-old woman presented with a right breast mass. Mammography showed a large asymmetrical density. Three fragments of rubbery breast tissue measuring 5 × 4 × 2.5 cm, 3 × 1.5 × 1 cm, and 2.2 × 1 × 0.5 cm were obtained through excision biopsy. Pathologic examination revealed breast tissue with gynecomastia-like changes and fibrocystic changes.

Case 3.—A 42-year-old woman presented with a left breast mass. Core biopsies showed infiltrating ductal carcinoma. A left radical mastectomy was performed. An area of gynecomastia-like changes was found incidentally (Figure 3).

Case 4.—A 19-year-old woman presented with a palpable right breast mass. Ultrasound evaluation failed to disclose a focal sonographic lesion. Core biopsy was performed. Three cylindrically shaped fragments of breast tissue measuring from 0.8 × 0.1 cm to 1.2 × 0.1 cm were obtained. Microscopic examination revealed ductal hyperplasia and periductal stromal edema with slight lymphocytic infiltrate. No terminal duct–lobular units were present in the area of involvement (Figure 4).

The analysis of these 4 cases is summarized in theTable.

The patients' ages ranged from 19 to 42 years, with a mean of 32 years. The usual clinical presentation was a palpable mass, except for one case (case 3) in which the patient had surgery for invasive ductal carcinoma and the gynecomastia-like change was an incidental finding. The available mammographic findings ranged from no specific findings even in the area of the palpable lump to a large asymmetric density. Gross examination of these specimens usually showed soft to slightly firm, irregular to ovoid masses of fibroadipose tissue. Histologically, the masses showed ductal hyperplasia with periductal stromal fibrosis or edema without presence of lobules, and these areas occupied at least 1 scanning power field (Figures 1 through 4). All lesions occupied only 1 or a few scanning power fields. Adjacent areas showed fibrocystic changes, such as cystic dilation and/or nonperiductal stromal fibrosis. Most of the patients had no significant medical history (Table).

The histologic pattern of the cases we discuss here was previously referred to as female gynecomastia-like changes. However, previous reports described only a few cases, and no specific histologic criteria were given for the diagnosis. In our review of prior reports, we noted that in some illustrations the lesions showed the presence of terminal duct–lobular units,8 which is not the finding in male gynecomastia, in which no terminal duct–lobular units are present. Our criteria stipulate that the lesions must not contain lobules.

The incidence of female gynecomastia-like change as defined in this study was 0.15% (4/2709) of all female breast lesions. Since not all 2709 breast surgical cases were reviewed, this survey represents an underestimation. Patients were usually young, ranging from 19 to 42 years old with an average of 32 years of age.

Rosen in his textbook briefly referred to and illustrated gynecomastia of the female breast.3 It is the same lesion we describe in our report. He indicated that it is rare and that it is indistinguishable from male gynecomastia. We add to his observation by offering a strict definition of the change and documenting its incidence. Previously, Rosen in collaboration with Oberman described and illustrated gynecomastia-type changes as a component of mammary hamartoma.4 The latter are sharply circumscribed masses of ducts and lobules with heterogeneous mixtures of dense connective tissue, adipose tissue, and less commonly smooth muscles or hyaline cartilage.4 The mammary hamartoma differs from the gynecomastia-like changes studied here, which merge gradually with normal breast and which have no components of cartilage or smooth muscle. Tavassoli5 in her text illustrated gynecomastia-like changes occurring in a case of juvenile hypertrophy. Similarly, Millis et al6 in the recent edition of a standard textbook illustrated gynecomastia-like change as a component of juvenile fibroadenoma. Our patients did not demonstrate the striking clinical and histologic findings of juvenile hypertrophy nor were the lesions well demarcated, as expected with a fibroadenoma.

Rosai7 described gynecomastia-like changes as a form of ductal hyperplasia, in agreement with the study of Tham et al.8 However, these authors described a purely ductal process with ductal epithelial hyperplasia similar to that seen in gynecomastia. These changes differ from the gynecomastia-like changes described by Rosen and by us3 in that their cases demonstrated the presence of lobules and absence of periductal changes.

In summary, we describe a rare histologic change seen in the female breast. It may be seen in other lesions of the breast (juvenile hypertrophy, juvenile fibroadenoma, or breast hamartoma), but in our cases it occurred as an incidental finding without specific clinical, mammographic, or gross findings. We believe it lies within the spectrum of fibrocystic change and is probably an expression of stromal overgrowth in the latter. It is a finding usually seen in younger women.

The etiology of this lesion is obscure. It is thought that male gynecomastia is the result of an imbalance between androgen and estrogen, with estrogen action exceeding that of androgen.9 All our cases had no significant medical history. The small number (4 cases) and the short follow-up does not permit evaluation of premalignant potential.

We conclude at this time that gynecomastia-like change of female breast is a benign pattern, is rare, and usually occurs in young patients. Although its clinical findings are nonspecific, it has a specific histologic pattern and probably should be subclassified within the spectrum of fibrocystic change, reflecting stromal predominance in fibrocystic change.

After submission of our manuscript, a report describing gynecomastia-like lesions in the female breast was published by Umlas (Arch Pathol Lab Med. 2000;124:844–847). In his report, he described gynecomastia-like lesions as a pure clinical entity. Four of his cases were palpable lesions and were entirely made up of gynecomastia-like changes. In contrast, our study indicated that our cases occurred as incidental findings and were without specific clinical, mammographic, or gross findings. We believe that our cases correspond to 3 additional cases that Umlas described as gynecomastia-like areas.