The Role of Preoperative MRI in Patients With Invasive Lobular Carcinoma Golan.O, Sperber.F, Shalmon.A, Weinstein.I, Gat.A Breast Imaging Department Tel-Aviv Medical Center

ILC accounts for 5-14% of breast malignancies. Invasive lobular carcinoma (ILC) was first described in 1946 by Foote and Stewart. ILC accounts for 5-14% of breast malignancies. Diagnostically ILC is challenging because of its veiled presentation on clinical examination and on imaging.

Histology ILC spreads through the breast parenchyma by means of diffuse infiltration of single rows of malignant cells in a linear fashion (Indian-file pattern) around nonneopolastic ducts. Little disruption of the underlying anatomic structures, Little surrounding connective tissue reaction The indistinctness on physical examination and imaging is most likely related to histological characteristics……This infiltration causes little disruption of the underlying anatomic structures and generates little surrounding connective tissue reaction

Invasive lobular carcinoma (ILC) of the breast is known to be substantially underestimated by mammography Because ILC frequently does not form a demonstrable mass or distort the architecture or commonly produce calcifications, and is frequently isodense with normal tissue, it is not unusual for ILC to go undetected on sequential mammograms until it becomes clinically evident. False negative 3-16% It is falsely negative in 3 to 16 %, moreover even when ILC is detected by mammography its extent is often underestimated because of its presentation as subtle architectural distortion as opposed to mass effect.

Mammographic Characteristics of ILC (Ellen B.Mendelson et al AJR) Asymmetric density without definable margins. A Mass with spiculated margins. No tumor discernible by mammography especially in dense breast tissue . Microcalcifications (rare) mendelson et al checked the Mammographic Characteristics of ILC Asymmetric density without definable margins was the most common pattern, A Mass with spiculated margins was the next most common presentation Dense breast tissue with no tumor discernible by mammography was relatively uncommon, 25% of the lesions contained calcifications but calcifications alone was rarely the reason for biopsy/

Ultrasound Appearance ILC cannot be distinguished from ductal carcinoma by ultrasound. Hypoechoic tissue is seen with varying degrees of posterior enhancement. In their retrospective review, Selinko et al found that ILC lesions were more easily seen on ultrasound than mammography. In their retrospective review of 62 pathologically proven ILC , Selinko et al found that ILC lesions were more easily seen on ultrasound than mammography,

Measurement of tumor size plays a pivotal role in treatment planning of breast cancer Breast conserving surgery VS Mastectomy Neoadjuvant chemotherapy ? Measurement of tumor size plays a pivotal role in treatment planning of breast cancer and deciding whether to do a lumpectomy or mastectomy and whether to give neoadjuvant chemotherapy prior to surgery

Objective To evaluate MRI ability to determine the extent of ILC compared to mammography and ultrasound, and to determine if ILC, as depicted on MRI, correlated with histopathological findings.

Materials and methods Retrospective study of 22 patients with biopsy proven ILC who underwent MRI (7/2005-9/2007) Age: 32-67 years (median 50 )

MRI technique MRI was performed using 1.5T magnet (signa GE) using 4 channels breast coil Imaging protocol: Bilateral parallel imaging T2 weighted sagittal fat suppressed T1 weighted dynamic sagittal fat suppressed 3D FSPGR before and following contrast Subtraction, curves of enhancement and MIP. Typical section thickness: 2-2.5 mm

Results

Mammographic findings Mass 55% Asymmetrical density 27% Calcifications 9% No mammographic findings 9%

Mammographic /ultrasound correlation No mammographic finding-multifocal irregular solid masses bilateral. Masses on mammography- irregular solid masses on US on 33% multifocal (versus 17% on mammography). Asymmetrical density on mammography- irregular solid masses on US. Calcifications on mammography- multifocal irregular solid masses on US .

MRI findings Pattern of enhancement: Masses 91% Focal irregular enhancement with no dominant mass 9% . In 27% irregular ductal enhancement was also present. 73% irregular spiculated 18% mass with irregular thick ring enhancement In 7 (64%) patients more than one mass, versus /////% on US and 17% on mammography.

Size: The median diameter of the dominant mass on MRI was 5.6cm (2.2-9cm) versus 2.7 cm (1.7-5.3cm) on US and 2.5 cm (2-5cm) on mammography. Extension of the disease: In 64% more than one mass versus 54% on US and 17% on mammography 3 multifocal 4 multifocal multicentric

MRI findings Curves of enhancement A strong and fast enhancement with washout 45% A more benign curve 55% (speed, intensity, washout) When we looked at the enhancement curves we found that only 45% had the typical malignant curve of strong and fast enhancement with washout whereas 55% had amore benign curves with A slower or weaker, enhancement and plateau

Pathologic correlation 27% had a mastectomy – the tumor size and the extent of the disease was much bigger than those we saw on mammography and US and had a good correlation with MRI findings. 73% were operated after neoadjuvant chemotherapy (3 mastectomy) – better correlation to the MRI than mammography and us. (1 patient) had a mastectomy – the size and the extent of the disease was much bigger than those we saw on mammography and US and had a good correlation with MRI findings. (1 patient) who had a mastectomy one week after the MRI– the size of the tumor and the extent of the disease according to the pathology report was much bigger than those we saw on mammography and US (the biggest diameter was 7 cm on MR versus 2 cm on mammo and 2.5 cm on US ) and had a good correlation with MRI findings. (4 patients) were operated after neoadjuvant chemotherapy (3 of them had a mastectomy) – even than there was a better correlation between MRI findings and pathology report in means of the size of the tumors and the extent of the disease. The other patients under neoadjuvant chemotherapy and weren't operated yet

54 years old who presented with a palpable mass on the right (UOQ) breast RT LT Mammography showed no findings accept from a known benign mass on the inferior part of the left breast.

RT RT

LT LT

42 years old who presented with a palpable mass on the right (uoq) breast On mammography we see a highly dense breast with a cluster of calcifications on the outer upper quadrant On US an irregular hypoechogenic mass was seen on 10 o'clock (2.1x1.3)

45 years old who presented with a palpable mass on the right (uoq) breast. BRCA carrier. On the left we can see the initial mammography with a 3 cm irregular mass on the breast tail, On the right a few months latter after 4 courses of neoadjuvant chemotherapy the mass is smaller measuring 1.5 cm with involution of most of the lymph nodes ..

MIP

43 years old who presented with a palpable mass on the right (uoq) breast Asymmetrical density with architectural distortion

MIP

Conclusions Invasive lobular carcinoma is the second most frequent invasive breast cancer. It is unusually discovered on screening mammography and the presenting symptom is commonly a palpable mass. Mammography is disappointing with a high rate of false negative. US improves the imaging of ILC but still does not show the full extent of the disease. MRI provides the most accurate estimation of tumor size and the extent of the disease, commonly showing us a multifocal disease which is underestimated by the conventional methods. MRI often modify the therapeutic strategy ruling out conservative procedures.

MRI of the breast should be considered as a preoperative routine patients diagnosed with Invasive lobular carcinoma.