Australasian Radiology (1 996) 40, 41 2-41 5

Ultrasonography of breast hamartomas J Black,’ C Metcalf2 and EJ Wylie’ ’Department of Diagnostic Radiology and ?Department of Pathology, Royal Perth Hospital, Perth, Western Australia, Australia

S U M MARY

The authors present the breast ultrasound findings of nine women with mammographic abnormalities typical of breast hamartomas. Two of the mammographically detected hamartomas could not be identified at breast ultrasound. Six hamartomas were well-circumscribed masses of heterogeneous echogenicity with no posterior acoustic shadowing. One lesion was a well-defined hypo-echoic mass with no posterior shadowing. We conclude that many mammographically and clinically detected hamartomas can be clearly identified at breast ultrasound. The breast sonographer should be aware of the spectrum of appearances that may occur. When a breast abnormality has the characteristic mammographic appearances of a hamartoma, it may be counterproductive to perform an additional breast ultrasound.

Key words: hamartoma; mammography; ultrasound.

INTRODUCTION Breast hamartomas are benign breast tumours composed of an admixture of glandular fat and fibrous tissue. These benign tumours are often discovered incidentally on screening mam- mography. With the increased availability of screening mam- mography, radiologists are more frequently encountering this benign lesion. While the mammographic characteristics of these lesions are well described, very few cases of hamartoma detected by ultrasound have been described in the radiologi- cal literature.

METHODS Nine patients aged 40-73 years with typical mammographic appearances of a breast hamartoma underwent ultrasound examination between April 1994 and April 1995. Four of the lesions were asymptomatic and detected at screening mam- mography. Four patients had a clinically palpable lump and subsequently underwent diagnostic mammography and one patient had a mammogram performed for sore breasts and nipple discharge. The screening mammograms were per- formed as part of the Western Australian Women’s Cancer Screening Service (WCSS). The diagnostic mammography was performed at Royal Perth Hospital Breast Assessment Clinic (RPH BAC) using a Siemens Mammomat II mammography unit. All ultrasound examinations were performed at the RPH BAC using a Toshiba 270 linear array 7.5 MHz probe. All nine

patients underwent cytologic examination with fine needle aspiration performed under mammographic or ultrasound control or free hand if the lump was palpable. One patient had a subsequent core biopsy performed and one patient came to excision biopsy.

RESULTS Two lesions were undetectable on ultrasound. This was despite knowledge of the marnmographic findings and the availability of the mammograms to direct the ultrasonographer to the area of interest.

Six lesions were well circumscribed but had a hetero- geneous ultrasonographic appearance. The appearances at ultrasound were all considered probably benign and a cyto- logical confirmation was sought so that women could be dis- charged back to a normal screening interval.

One lesion was shown to be a well-defined hypo-echoic mass. The ultrasound appearance could not be differentiated from a fibroadenoma and consequently histological confirma- tion was required.

All nine lesions had cytological or histological confirmation of a hamartoma. The palpable lesions underwent free hand fine needle aspiration or fine needle aspiration under stereo- tactic or ultrasound guidance. One lesion had a subsequent core biopsy performed and one lesion came to excision biopsy.

J Black; C Metcalf; EJ Wylle Correspondence: Dr J Black, Department of Diagnostic Radiology, Royal Perth Hospital, GPO Box X2213, Perth, WA 6001, Australia. Submitted 15 December 1995; accepted 8 February 1996.

ULTRASONOGRAPHY OF BREAST HAMARTOMAS 41 3

DISCUSSION The term breast hamartoma was first coined in 1971 . l Subse- quent terms used to describe the lesions have included lipo- fibroadenomas, adenolipomas and fibroadenolipomas2. They are benign breast tumours composed of variable admixtures of glandular fat and fibrous tissue. Hamartomas are typically circumscribed but lack a true c a ~ s u l e . ~ Clinically, hamartomas are soft and well circumscribed. Their consistency and texture is similar to normal surrounding breast tissue, making them frequently difficult to ~a lpa te .~ They are often discovered inci- dentally on screening mammography.

The mammographic appearances of breast hamartomas are said to be characteristic. Typically, the lesion is well cir- cumscribed and composed of both stromal and lipomatous elements. They are said to resemble a slice of cut salami or cauliflower. Often, there is a thin fibrous rim visible on the

mammogram. The key to the mammographic diagnosis is rec- ognition of the mixed density of the leSiOn.3,4m5

There have been few studies concerning the ultrasono- graphic appearances of breast hamartomas. Kopans et a/. in a SolitaV case report described a heterogeneous appearance

Fig. 1a,b Heterogeneous mass on ultrasound at site of palpable mass.

Fig. 2a,b Heterogeneous mass on ultrasound at site of well-circum- scribed calcified retroareolar mass detected at screening mammography.

41 4 J BLACK ET AL.

and commented that an increased awareness of this lesion would be useful for those involved in breast ultrasound. Adler et aL6 reported sonographic findings in 10 harnartornas and concluded there was too wide a spectrum of appearance for diagnostic usefulness.

We conclude that many mammographically and clinically detected hamartomas can be clearly identified at breast ultra- sound. There is, however, a wide spectrum of appearances. While many of the lesions are heterogeneous, presumably reflecting the mixed fatty and fibrous nature of these lesions, some hamartomas appear homogeneously hypo-echoic and may mimic fibroadenomas or occasionally a well-circumscribed carcinoma. Consequently, the ultrasound appearances may

Fig. 3a,b Heterogeneous mass on ultrasound at site of large impal- pable mass detected at screening mammography.

Flg. 4a,b Well-circumscribed, heterogeneous, predominantly hypo- echoic mass at site of palpable and mammographically detected mass in left axillary tail region.

ULTRASONOGRAPHY OF BREAST HAMARTOMAS 41 5

Fig. Ba,b Well-defined hypo-echoic mass on ultrasound at the site of palpable and mammographically detected mass.

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Fig. Sa,b Relatively well-circumscribed, heterogeneous mass at site of impalpable mass detected at screening mammography.

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