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2003 Blackwell Publishing, Inc., 1075-122X/03/$15.00/0The Breast Journal, Volume 9, Number 3, 2003 246–248

Address correspondence and reprint requests to: Marc Baron, MD,Département de Chirurgie, Center Henri Becquerel 80, rue d’Amiens, 76000Rouen, France, or email: baron.marc@voilà.fr.

Blackwell Publishing Ltd.Oxford, UKTBJThe Breast Journal1075-122X2003 Blackwell PublishingMay–June 200393BREAST IMAGESInvasive Lobular Carcinoma in a Breast Hamartoma

baron et al

.

BREAST IMAGES

Invasive Lobular Carcinoma in a

Breast Hamartoma

Marc Baron, MD,* Jean-Marie Ladonne, MD,* Antoine Gravier, MD,* Jean-Michel Picquenot, MD

†

and Michel Berry, MD

‡

Departments of *Surgery,

†

Pathology, and

‡

Radiology, Center Henri Becquerel, Rouen, France

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Abstract:

Hamartomas are uncommon benign breastneoplasms. We report the first case, to our knowledge, of inva-sive lobular carcinoma arising in a breast hamartoma. Thiscase illustrates the importance of careful interpretation ofthe clinical and mammographic findings. A more aggressiveapproach toward the management of breast hamartomas isnot justified when clinical and mammographic findings are con-sistent with classic hamartomas.

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Key Words:

breast hamartoma,

invasive lobular carcinoma

H

amartomas are uncommon benign breast lesionscomposed of varying amounts of fatty, fibrous,

and glandular elements (1). We report a case of invasivelobular carcinoma arising in a breast hamartoma.

CASE REPORT

A 54-year-old premenopausal woman was referredfor evaluation of a breast hamartoma diagnosed 3 yearspreviously by clinical, mammographic, and histologicfeatures. The cytology made on a fine-needle aspirationshowed benign epithelial cells. The patient presentedwith a soft, round, mobile lump located in the upperouter quadrant of the right breast. The mass had notincreased in size (4 cm in diameter), but recent testsrevealed changes in the appearance of microcalcifications

in the well-circumscribed oval, mixed fatty and fibroglan-dular lesion which was present in previous mammograms(Fig. 1). These microcalcifications were fine, irregular,and pleomorphic. They were classified as category 4in the American College of Radiology Breast Imagingand Reporting Data System (ACR BI-RADS). The lumpwas easily removed by simple enucleation.

Histologically the lesion subsequently proved to be a20 mm invasive lobular carcinoma confined to the hamar-toma which measured 50 mm

×

40 mm

×

25 mm (Fig. 2).Microcalcifications were located only in the epitheliosiswithout atypical features discovered within the hamar-toma (Fig. 3). A right axillary dissection was performedand there was no node involvement. Hormone receptoranalysis showed high estrogen receptor (ER) and lowprogesterone receptor (PR) levels. The patient is currentlybeing treated with tamoxifen and radiation therapy.

DISCUSSION

Breast hamartoma is commonly described as a rare,benign lesion with a classical mammographic appearance.Clinically concealed as fibroadenoma, it may be difficultto palpate because of its similarity to surrounding normalbreast tissue.

Arrigoni et al. (1) introduced the term breast hamar-toma and emphasized the encapsulation, macroscopic,and microscopic characteristics of such a lesion. Macro-scopically breast hamartomas are well-delineated tumorswith a smooth, glistening surface, often lens shaped.Histologic examination reveals a combination of epithe-lial and stromal elements. The glandular elements arerandomly dispersed with varying degrees of lobular

Invasive Lobular Carcinoma in a Breast Hamartoma •

247

distortion; small cysts are frequently found and epithelialhyperplasia is rarely seen. In some cases the histologyis that of normal breast tissue. The pattern of the stromais variable: densely fibrous and hyaline, extending into

the lobules and obliterating the intralobular tissue; theamount of stromal fat is variable.

Only four cases of carcinoma in hamartomas have pre-viously been documented: one lobular carcinoma in situwith two small foci of microinvasive lobular carcinoma(2), two invasive ductal carcinomas (3), and one in situand invasive ductal carcinoma (4). Here we report thefirst case, to our knowledge, of invasive lobular carcinomaoccurring in a mammary hamartoma. It seems likelythat its occurrence is coincidental. Because of its histologicsimilarity with normal breast tissue (1), breast hamartomamay undergo malignant changes. Two cases of breasthamartoma with invasive ductal carcinoma presentedwith a firm area which in one case ulcerated the skin (3).A firm lymph node in the axilla was palpated in the thirdcase (4). In this report, only radiographic abnormalities

Figure 1. (a) Mediolateral oblique and (b) craniocaudal mammogramsdemonstrated a mixed-density encapsulated lesion with fine andirregular microcalcifications.

Figure 2. Histopathologic view of mammary hamartoma infiltrated byinvasive lobular carcinoma (magnification ×40).

Figure 3. Histopathologic view of invasive lobular carcinomasurrounding lobular benign glands with microcalcifications(magnification ×100).

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were suggestive of malignancy and these unusual findingsdo not justify a more aggressive approach toward themanagement of mammary hamartomas.

Breast hamartoma can be diagnosed mammographi-cally with a high degree of assurance when a circum-scribed area consisting of both soft tissue and lipomatouselements is found surrounded by a thin radiolucent zone.Because a hamartoma can be considered a “breast in thebreast,” calcifications could develop inside it. They are theconsequence of benign processes and never should appearas malignant calcifications. Thus the ACR BI-RADS cat-egory is 2 or 3. When the mammographic appearance isclassical, excisional biopsy can be avoided; but this is lesscommon than previously reported because of the earlierdetection of small hamartomas. Helvie et al. (5) reported17 women with pathologically proven mammary hamar-tomas. In two cases only, the classical findings for hamar-toma were described and five patients did not present withmammographically detectable masses.

Ultrasound should have a minimal role in the diagnosisof breast hamartoma in view of the wide sonographic var-iability (6). The most common sonographic appearanceis a well-circumscribed, solid hypoechoic mass with poste-rior acoustic shadowing. This appearance is not specificand has been reported for carcinoma.

In conclusion, breast hamartoma is a benign lesionand carcinoma only rarely occurs within it. The low riskof discovering a carcinoma within it and the frequentatypical mammographic findings are sufficient reasons for

counseling against systematic surgical removal or biopsy.Such an attitude must depend on other considerations relatedto classical aspects of breast cancer diagnosis, including forinstance the appearance of suspicious microcalcifications.

Acknowledgments

We thank Mrs. M.-C. Vuillermoz-Fawcett, Departmentof Clinical Biochemistry, Medical School, NewcastleUpon Tyne, NE2 4HH, UK, for reviewing the Englishmanuscript.

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