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JBDJournal of Breast Disease

Huge Bilateral Breast Hamartoma Accompanied with Pseudoangiomatous Stromal HyperplasiaHyungJoo Baik, Jin Woo Kim1, Young Mi Park2, Soo Jin Jung3, Anbok Lee, Hye-Kyoung Yoon3, Tae Hyun KimDepartments of Surgery, 1Plastic Surgery, 2Radiology, and 3Pathology, Inje University Busan Paik Hospital, Inje University College of Medicine, Busan, Korea

A 34-year-old woman presented with sudden breast enlargement that had occurred within 6 months. She also had an accessory breast mass on the left axilla. Clinical impression was phyllodes tumor. Needle biopsy revealed fibroepithelial tumor, a mixture of fibrous stroma and pseudoangiomatous stromal hyperplasia. The final pathologic report was hamartoma associated with focal pseudoangiomatous stromal hy-perplasia and macromastia. This is the first reported case of bilateral breast hamartoma with hamartoma in ectopic breast tissue. The mass-es on the right and left breasts weighed 1,980 g and 1,233 g, respectively, while the mass on the left axilla weighed 36 g.

Key Words: Gigantomastia, Hamartoma, Pseudoangiomatous stromal hyperplasia

INTRODUCTION

Breast hamartoma is an uncommon benign disease of the breast,

accounting for 4.8% of all benign breast masses [1]. Hamartomas com-

prise varying proportions of fat, fibrous, and adenomatous elements,

which result in different radiologic and pathologic findings. Thus,

hamartomas are easily confused with other well-circumscribed, be-

nign breast diseases such as phyllodes tumors and fibroadenomas.

Moreover, breast hamartoma is usually found unilaterally, ranging in

size from 0.9 to 6.9 cm [1].

Herein, we report an unusual case of huge bilateral breast hamarto-

ma with hamartoma in axillary ectopic breast tissue.

CASE REPORT

A 34-year-old woman visited Breast Center of Inje University Busan

Paik Hospital for the evaluation of hard bilateral breast masses; the

right and left masses were 25 cm and 18 cm in size, respectively (Figure

1A). She had no medical history, and her family did not have any

breast-related medical history. The patient was not married and had

no children. The patient’s previous breast size was A cup, but her

breasts had gradually enlarged to the aforementioned size in only 6

months. She also had a mass on her left axilla.

The masses were a conglomeration of multiple well-defined hetero-

geneously hypoechoic masses, occupying almost the entirety of both

breasts on ultrasonography. Some of the masses had internal slit-like

anechoic spaces that are frequently found in phyllodes tumors or

pseudoangiomatous stromal hyperplasia (PASH). Markedly increased

vascular signals in the masses were seen on color Doppler images. A

well-circumscribed hypoechoic mass showing ultrasonographic fea-

tures similar to those of the breast masses was also seen in the left axil-

la. Normal breast parenchymal tissue was not observed. The ultraso-

nographic pattern was suggestive of multiple fibroadenomas, phyl-

lodes tumor or PASH (Figure 2A, B).

Huge well-circumscribed, soft tissue masses of heterogeneous signal

intensity were seen in both breasts on axial T1/T2-weighted magnetic

resonance imaging (MRI) (Figure 2D). Sagittal dynamic contrast-en-

hanced MRI showed strong heterogeneous multilobular enhancing

masses that resembled orange slices. Time-intensity analysis indicated

early rapid initial rise and washout kinetics. Diffusion-weighted MRI

showed multifocal, multicentric high signal intensity. These MRI

findings suggested the possibility of malignancy (Figure 2C, D). The

kinetic features of the tumor were attributable to the increased vascu-

larity of the masses, as seen on color Doppler ultrasonography.

Needle biopsy of the right breast mass (12 o’clock site) was sugges-

tive of either a fibroepithelial tumor or PASH. The possibility of phyl-

CASE REPORTJ Breast Dis 2016 June; 4(1): 28-32http://dx.doi.org/10.14449/jbd.2016.4.1.28

Correspondence: Tae Hyun KimDepartment of Surgery, Inje University Busan Paik Hospital, 75 Bokji-ro, Busangjin-gu, Busan 47392, KoreaTel: +82-51-890-6352, Fax: +82-51-890-6352, E-mail: kitah@hanmail.netReceived: Mar 29, 2016 Revised: May 10, 2016 Accepted: May 25, 2016

http://dx.doi.org/10.14449/jbd.2016.4.1.28 http://www.jbd.or.kr

An Unusual Benign Breast Tumor Mistaken as Phyllodes Tumor 29

Figure 1. Physical findings. (A) Preoperative findings. (B) Postoperative findings.

Figure 2. Radiologic findings. (A) Circumscribed multinodular heterogeneously hypoechoic masses showed in right and left entire breasts on ultrasonography. A circumscribed hypoechoic mass in the left axilla with ultrasonographic features similar to those of the breast masses was also observed (not shown). (B) Color Doppler sonogram shows markedly increased vascular signals. (C) The color-coded kinetic pattern of the magnetic resonance imaging (MRI) indicates early rap-id initial rise and washout kinetics (yellow and red colors), suspicious for malignancy. (D) Huge circumscribed, conglomerated, soft tissue masses of heteroge-neous signal intensity on axial T2-weighted MRI are filled in both breasts, instead of normal breast tissue.

A

A

C

B

B

D

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30 HyungJoo Baik, et al.

lodes tumor accompanying malignancy could not be ruled out, even

though the results of the needle biopsy suggested benign diseases.

The patient underwent bilateral mastectomy followed by immedi-

ate implant reconstruction (Figure 1B). In order to ensure safety mar-

gin of the tumor, subcutaneous mastectomy including overlying skin

excision was done. Excised right and left breast masses were 25× 19

cm and 21 × 18 cm in diameter, respectively. Cut sections of both

breast masses showed similar features with multinodular appearance

and focal fibromyxoid areas. The left axillary mass measured 5.5× 4.4

cm, with yellowish white nodules on the cut section (Figure 3). The

Figure 4. Microscopic and immunohistochemical findings. (A) Focal lobular arrangement of breast parenchymal tissue is seen in both breasts (H&E stain, ×40). (B) Focal pseudoangiomatous stromal hyperplasia is seen (H&E stain, ×100). (C) Stromal tissue of the mass is positive for CD34 (immunohistochemical stain, ×40). (D) Stromal tissue of the mass shows focal weak positivity for epidermal growth factor receptor (immunohistochemical stain, ×40).

A

C

B

D

Figure 3. Postoperative breast specimen. (A) Right breast mass was 25×19 cm. (B) Left breast mass was 21×18 cm and axillary mass was 5.5×4.4 cm. Weight of each mass was 1,980 g on the right, 1,233 g on the left, and 36 g on the axilla.

A B

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An Unusual Benign Breast Tumor Mistaken as Phyllodes Tumor 31

masses on the right and left breasts weighed 1,980 g and 1,233 g, re-

spectively, while the mass on the left axilla weighed 36 g.

Microscopically, both breast masses exhibited similar histologic

features with relatively well-demarcated borders. Benign-looking

breast parenchymal tissue showed multinodular growth, with focal

PASH (left-sided mass) and lymphangiectasia (right-sided mass) in

the stromal tissue. Pathologically, the patient was diagnosed with

mammary hamartoma. Immunohistochemical staining of the left-

sided mass revealed that the cells were positive for CD34, focally posi-

tive for epidermal growth factor receptor (EGFR) and negative for

smooth muscle actin. The excised left axillary mass was diagnosed as

hamartoma arising from the accessory breast tissue (Figure 4).

The results of the hormone essays were as follows: estradiol, 290 pg/

mL; follicle-stimulating hormone, 2.02 mlU/mL; prolactin, 9.16 ng/

mL; and progesterone, 13.02 ng/mL. All these results were within nor-

mal ranges. Twelve months after the surgery, the patient has not expe-

rienced any complications or tumor recurrence.

DISCUSSION

We performed surgery for an unusual case of macromastia con-

firmed as bilateral breast hamartoma, with hamartoma in axillary ec-

topic breast tissue.

The definition of macromastia or gigantomastia varies, but the

most common definition is breast enlargement that requires breast

reduction surgery to remove >1,800 g of tissue on each side [2]. Dif-

ferential diagnosis for breast hypertrophy includes virginal hypertro-

phy, gravid hypertrophy, fibroepithelial tumors, traumatic hypertro-

phy, and pseudohypertrophy due to obesity, in addition to endocrine

abnormalities [3]. Because hamartoma is an excess of normal tissue,

our patient’s cause of breast hypertrophy is thought to be due to ham-

artoma itself. The reason the patient’s breasts had markedly enlarged

from A cup-sized breasts to gigantomastia within only 6 months is

still unclear. However, because her estrogen and progesterone levels

were within normal ranges, and the immunohistochemistry stain for

EGFR was focally positive, it could be speculated that her breast pa-

renchyma had become hypersensitive to estrogen, progesterone or

certain growth factors.

Breast hamartoma is an uncommon benign breast disease, and its

pathogenesis is yet to be elucidated. Most breast hamartomas are

found unilaterally; very few cases of bilateral breast hamartomas have

been reported, and, to date, no case of bilateral breast hamartoma

with hamartoma in ectopic breast tissue has been reported [4]. Sizes of

hamartomas vary from as small as a few centimeters to 25 cm. The

conglomeration of radiologic and pathologic findings is important in

the diagnosis of hamartomas. Depending on the varying proportions

of fat and fibroglandular tissue, radiologic studies show inconsistent

traits, making diagnosis difficult. It is widely known that the diagnos-

tic value of needle biopsy in breast hamartoma is very limited, often

misdiagnosing as fibroadenoma or other benign diseases [5]. There-

fore, complete excision of hamartoma is imperative in the diagnosis.

Radiologically, hamartomas have a mammographic appearance

typical of lucent lesions containing fat, varying proportions of ra-

diodense fibrous and adenomatous elements, sharp margins, and in

some cases, a thin capsule [6]. The role of ultrasonography in the diag-

nosis of hamartomas is limited because hamartomas may have a wide

range of ultrasonographic appearances. In a study by Chao et al. [7],

breast hamartomas are well-circumscribed, solid, oval tumors with-

out intratumoral microcalcification. The internal echo texture of

most hamartomas is either hyperechoic or of mixed echogenicity.

They are often described as a “slice of salami” [8]. Characteristic MRI

findings of hamartomas include heterogeneous intensities on conven-

tional T1- and T2-weighted MRI, which correlate with their fatty, fi-

broglandular contents and thin capsule [5].

Pathologically, a definite diagnostic criterion for hamartoma is still

lacking; however, a hamartoma consists of a mixture of benign epithe-

lial elements, fibrous tissue, and fat. Normal compressed tissue along

the periphery of the mass is another significant pathologic finding [7].

Our case was diagnosed as hamartoma with PASH. PASH was first

described by Vuitch et al. [9] in 1986, indicating a benign breast dis-

ease with focal proliferation of fibroblast and myofibroblast cells. The

breast stromal tissue contains vessel-like structures with increased

collagenous tissue [10]. However, there are no red blood cells in these

vessel-like structures, and spindle cells, without atypia, are found;

along this space, these spindle cells are positive for vimentin, CD34,

actin, and desmin but negative for cytokeratin or factor VIII-related

antigens. Additionally, fibroblast-like features are observed on elec-

tron microscopy. The presence of these vessel-like cavities with spin-

dle cells means that PASH is often mistaken for low-grade angiosar-

coma. Although spindle cells are factor VIII-related antigen-negative,

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32 HyungJoo Baik, et al.

it is difficult to diagnose PASH if the pathologist is unaware of its clin-

ical and pathologic features [11].

In cases with huge benign breast masses, surgeons must consider

that, although needle biopsy may suggest fibroadenomas or other tu-

mors, final diagnosis may be otherwise. In cases such as the one re-

ported here, when breast mass is huge and the pathology of needle bi-

opsy is ambiguous, surgery is mandatory for both the confirmatory

diagnosis and for the proper management of the tumor, as well as to

fulfill the patient’s cosmetic needs.

CONFLICT OF INTEREST

The authors declare that they have no competing interests.

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