MRI Features of Synchronous Masses in Known Breast Cancer Patients in Predicting Benign Versus Malignant Lesions: A Case Based Review at Tertiary Care Cancer Hospital

Objectives The purpose of this study was to determine the diagnostic accuracy of breast magnetic resonance imaging (MRI) in classifying incidental satellite masses in biopsy-proven breast cancer patients as benign or malignant masses and assessing its impact on surgical management of these patients. We also analyzed the incidence of MRI-detected lesions, which were thereafter assessed with second look ultrasound (US). Materials and Methods A retrospective study was performed on breast cancer patients presenting from August 01, 2016 to July 31, 2019, with satellite masses seen on base line MRI. Satellite masses were classified as benign and malignant based on MRI features of shape, margin, T2-weighted imaging signals, internal enhancement pattern, enhancement kinetic curves, and diffusion restriction. This was compared with results of histopathological examination. The number of MRI-detected lesions, location of the satellite mass, and type of surgery were also documented. Results Out of 400 breast cancer patients undergoing MRI breast, 115 patients had multiple masses. Histopathological diagnosis was available for 73 patients; and a total of 93 satellite masses were evaluated. There was evidence of additional masses on second look ultrasound in 21 patients. Of 72 masses classified as malignant on MRI, 58 showed malignant pathological outcome; while out of 21 masses characterized as benign on MRI, 18 turned out to be benign on histopathology. A statistically significant association was found between MRI features and pathological outcome of satellite masses ( p = 0.001). The sensitivity, specificity, positive and negative predictive values, and accuracy were 95%, 56%, 80.56%, 85.7% and 81.7%, respectively. Based on these findings, modified radical mastectomy (MRM)/mastectomy was done for 42 patients, 5 patients underwent lumpectomy limited to a single tumor, extended resection done for 14 patients, 5 underwent bilateral breast conservation surgery (BCS), BCS for contralateral breast done for 4 patients undergoing ipsilateral MRM/mastectomy, and bilateral MRM/mastectomies were performed for 2 patients. One patient was lost to follow up. Conclusion Breast MRI is the most sensitive modality for the assessment of breast cancer and plays an essential role in the detection of additional tumor foci. These findings can modify the surgical approach in these patients. However, considering the low specificity, biopsy of satellite masses is imperative to determine the most appropriate surgical plan.