Summary: A 74-year-old female presented for routine screening mammography. She
had undergone screening mammography yearly for the past several years,
and her mammogram last year was interpreted as normal. She underwent a
surgical right breast biopsy 32 years ago that yielded benign results,
and had no family history of breast cancer. She has used hormone
replacement therapy since menopause.
Diagnosis
Stage T1c, N0, M0 stage 1 left breast cancer
Findings
A 2-dimensional (2D) mammogram revealed heterogeneously dense breast
tissue without focal masses or asymmetries and without changes when
compared to earlier mammograms (Figure 1).
A 3-dimensional (3D)
mammogram revealed an area of architectural distortion in the lateral
aspect of the left breast, seen on the CC tomosynthesis view only
(Figure 2), estimated to be at the 3 o’clock position based on its
tomosynthesis slice number.
The patient was asked to return for
additional mammographic views and an ultrasound. CC and MLO
spot-compression views demonstrated no definite abnormality in this area
(Figure 3), but a targeted ultrasound revealed a 5.5-mm spiculated mass
at the 3 o’clock position (Figure 4).
Discussion
Pathology results yielded an infiltrating and in-situ carcinoma, with
the well-differentiated infiltrating component measuring 1.1 cm and
demonstrating tubulolobular features, nuclear grade 2, ER/PR receptor
positive, HER 2/neu receptor negative. The grade 2 in-situ component
measured 0.3 cm. Other associated findings included a radial scar,
multifocal atypical ductal hyperplasia, and lobular intraeithelial
neoplasia. Two left-axillary sentinel lymph nodes were negative for
metastatic carcinoma.
The patient underwent a
mammographically-guided needle localization and a lumpectomy (Figures 5
and 6), followed by whole breast radiation therapy. She was advised to
cease hormone replacement therapy.
Breast tomosynthesis enabled
us to detect a small, early stage carcinoma in this patient with dense
breast tissue, while there was no abnormality detected on conventional
2D digital mammography. Findings seen in one view only on conventional
2D mammography frequently present a significant challenge. In this
instance, the finding was seen on the CC tomosynthesis view only and we
were able to localize this finding to the 3 o’clock position in the
breast secondary to its tomosynthesis slice position.
Digital
breast tomosynthesis is a novel technique that allows the visualization
of fibroglandular breast tissue in multiple planes rather than in just 2
planes of conventional 2D mammography, thereby enabling the radiologist
to better evaluate the configuration of areas of fibroglandular tissue.
As all radiologists who read mammograms know, breast tissue has an
extremely varied appearance with no 2 breasts being alike. The detection
of early malignant changes within normal fibroglandular tissue,
particularly in dense breasts,has been a longstanding challenge.
Tomosynthesis may assist us in discerning small areas of distortion and
spiculation within tissue that appears unremarkable on 2D mammography.1
Conclusion
Three-dimensional breast tomosynthesis may allow the detection of small
cancers, which could otherwise remain unseen until they become
significantly larger or even palpable. It may be superior to spot
compression views in the evaluation of asymmetries and architectural
distortion.
- Svahn, TM, Chakraborty, DP, Ikeda D, et. al. Breast tomosynthesis and digital mammography: A comparison of diagnostic accuracy. BR J Radiol. 2012;85: e1079-1082.