Objective: The objective of our study was to characterize the MRI features of breast carcinomas detected in augmented breasts.
Materials and methods: A review of the MRI database identified 54 patients with biopsy-proven breast carcinoma in augmented breasts. The images were reviewed for the type and location of the implant and for the characteristics of the carcinoma. The cases included 46 (85%) invasive cancers (invasive ductal carcinoma, n = 35; invasive lobular carcinoma, n = 7; and mixed features, n = 4) and eight (15%) ductal carcinomas in situ.
Results: The median age of the patients at diagnosis was 49 years (range, 28-72 years). Thirty-eight of the 54 cancers (70%) were palpable. The mean tumor size was 2.8 cm (range, 0.6-9.6 cm). Of the 54 cancers, 34 (63%) presented as masses and 20 (37%) as nonmass enhancement on MRI. There was no detectable difference between implant position and lesion morphology (p = 0.55) or tumor size (p = 1.00). Twenty of 54 (37%) carcinomas abutted the implant, 13 (24%) abutted the pectoralis major muscle, and two (4%) invaded the pectoralis major muscle. Of the tumors abutting the implant, 18 of 20 (90%) spread along the implant capsule for more than 0.5 cm. This pattern of tumor spread was more common in breasts with retroglandular implants (9/16, 56%) than in those with retropectoral implants (9/38, 24%) (p = 0.03). MRI detected the index carcinoma in 16 of 54 (30%) cases, showed a greater extent of disease than was visible on mammography or ultrasound in 21 of 52 (40%) cases, and detected an unsuspected contralateral carcinoma in three of 54 (6%) cases.
Conclusion: In augmented breasts, breast cancer often contacts either the implant or the pectoralis major muscle. Tumor spread along the implant contour is more often seen with retroglandular implants than with retropectoral implants. MRI should be considered to assess disease extent in women with augmented breasts before surgery.
Keywords: MRI; augmentation; breast carcinoma; implants.