Published 17 September 2008, doi:10.1136/bmj.a1313
Cite this as: BMJ 2008;337:a1313

Endgames

Picture Quiz

Breast imaging

¹ Cambridge Breast Unit, Addenbrooke’s Hospital, Cambridge CB2 2QQ

Case history

The figure shows the left and right mammograms of an 81 year old woman with a short history of a lump in the right breast. Clinical examination showed a mass in the upper outer quadrant, which felt as if it might be a breast carcinoma.

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Questions

1. What is shown in the right breast?

2. What is shown in the left breast?

3. What would be the next step in investigating this patient?

Answers

Short answers

1. An asymmetric density superiorly with some parenchymal deformity. Core biopsy showed an invasive lobular breast carcinoma.

2. A partially well defined mass inferiorly. In a patient of this age even a well defined mass suggests malignancy. Core biopsy showed an invasive ductal carcinoma.

3. Such patients undergo "triple" assessment—clinical examination, imaging, and, if necessary, needle biopsy in a multidisciplinary breast clinic.

Long answer
Any patient with a new breast lump should be referred to a specialist multidisciplinary breast clinic. Modern breast assessment consists of triple assessment—expert clinical examination, imaging (usually mammography and ultrasonography), and, if necessary, needle biopsy.¹ The single most important risk factor for breast cancer is age, with the incidence of breast cancer rising throughout life. A patient presenting with a new discrete lump at the age of 81 years is at substantial risk of having a malignancy.² Mammography is the first line imaging investigation for women over the age of 35 years.³ The mammographic features of benign and malignant lesions often overlap,⁴ and the table sets out the more common causes of different mammographic lesions.

View this table: [in this window] [in a new window]   Potential causes for various mammographic features and their relative risks

 
The patient’s right mammogram reveals an area of asymmetric density and parenchymal deformity (fig 2). This area, when corresponding with a palpable abnormality, is highly suggestive of malignancy. In the left breast there is a partially well defined, partially ill defined mass inferiorly. Well defined masses are more often seen in benign lesions, but in a patient of this age all focal mass lesions should be treated as suspicious for malignancy. It is important to note that mammography does not detect all breast cancers and has a sensitivity of 80-90%.⁵

View larger version (43K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Fig 2 Right and left mammograms of 81 year old woman showing an asymmetric density superiorly with some parenchymal deformity in the right breast and a partially well defined mass inferiorly in the left breast

 
Further evaluation of palpable and mammographic abnormalities is best undertaken with breast ultrasonography. State of the art ultrasonographic equipment, with high frequency (12-16 MHz) linear probes, has extremely high spatial resolution and is capable of exquisite visualisation of small lesions. This non-invasive, safe, and readily available modality can distinguish between cystic and solid lesions and whether the latter are likely to be benign or malignant.⁶ Ultrasonography of the patient’s right breast reveals features typical of a breast carcinoma (fig 3). The mass lesion is irregular in outline, has reduced echogenicity, and casts a posterior acoustic shadow. This reflects the cancer’s irregular margin and its fibrous content, which absorbs the ultrasound signal.

View larger version (103K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Fig 3 Ultrasonography of the right breast lump, showing features typical of a breast carcinoma: the mass lesion is irregular in outline, with reduced echogenicity, and casts a posterior acoustic shadow

 
Any focal solid or clinically suspicious abnormality requires pathological confirmation in the form of a needle biopsy, which is increasingly core biopsy under ultrasound guidance.⁷ Bilateral breast carcinomas were confirmed in this patient. Within the left breast core biopsy revealed an invasive ductal cancer of no special type. This is the commonest histological type of carcinoma, accounting for 75% of breast cancers.⁸ The commonest mammographic appearance of such tumours is that of a mass with spiculated or irregular margins.⁹

Core biopsy of the right breast mass revealed an invasive lobular malignancy. This accounts for 10-15% of breast cancers.⁸ Most such cancers have mammographic features indistinguishable from ductal carcinomas. About a third of lobular carcinomas, however, have a permeative, infiltrating growth pattern that may result in vague asymmetrical densities or parenchymal deformities in mammograms.¹⁰ Such carcinomas may also feel clinically innocuous and be hard to visualise by ultrasonography, particularly in women with dense breasts, and can therefore present a diagnostic challenge. A definitive preoperative diagnosis of malignancy enables patients to be satisfactorily counselled and definitive treatment, usually surgery, to be planned. Any surgery for invasive breast cancer also involves accurate staging of the axillary lymph nodes, usually by means of a sentinel lymph node biopsy.¹¹

Patients with newly diagnosed breast cancer now often undergo axillary ultrasonography and either fine needle aspiration cytology or core biopsy in an attempt to diagnose lymph node metastasis before surgery and thus prevent unnecessary sentinel lymph node biopsies.¹² Pathological nodes may exhibit a variety of ultrasonographic features. The absence of a fatty hilus is well known as suspicious, but not pathognomonic, for malignancy (fig 4). A lymph node with a cortical thickness of >2 mm is associated with malignancy in 30% of cases and with benignity in 70%.¹³ A lobulated cortex is found in about 20% of malignantly involved nodes and is associated with malignancy in 53-73% of cases. However patients with morphologically normal nodes (fig 5) may be found to have metastases in 28% of cases (range 16-52%).^{13 14}

View larger version (93K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Fig 4 Ultrasonography of an axillary lymph node showing the absence of a fatty hilus, a well recognised feature suspicious, but not pathognomonic, for malignancy

 

View larger version (125K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Fig 5 Ultrasonography of an apparently normal axillary lymph node. Although it is large, being 32 mm in maximum longitudinal dimension (A) and 11 mm wide (B), it is mainly made up of fat with only a thin rim of cortex measuring 1.5 mm in thickness (C)

 
The variable accuracy of such findings requires needle biopsy confirmation of metastases. Results to date show that 21-63% of lymph node metastases can be diagnosed with ultrasound guided needle biopsy.^{15 16} A negative result does not exclude metastatic disease, however, and such patients still require sentinel lymph node biopsy.

Although mammography and ultrasonography are central to breast cancer diagnosis, both have limitations in accurately showing the extent of certain breast cancers. For this reason dynamic, contrast enhanced, magnetic resonance imaging is increasingly being used to stage newly diagnosed breast cancer. Breast magnetic resonance imaging has sensitivities between 89% and 100% for invasive disease,^{17 18} revealing otherwise unsuspected additional sites of tumour in 16% of patients (fig 6).¹⁹ The exact role of breast magnetic resonance imaging and who would most benefit from this expensive technology are still to be established.²⁰

View larger version (28K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Fig 6 Subtraction 3D maximum intensity projection of dynamic enhanced magnetic resonance imaging of patient’s breasts shows two tumour foci in the right breast (solid arrows) and two in the left breast (broken arrows). Multifocal disease, which was unsuspected at the time of initial mammography and ultrasonography, was confirmed at subsequent bilateral mastectomies

 
Cite this as: BMJ 2008;337:a1313

Competing interests: None declared.

Patient consent obtained.

References

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Investigation of suspected breast cancer

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