MR Appearance of Metastatic Melanotic Melanoma in the Breast: Case Reports

Abstract

A 34-year-old Chinese woman complaining of multiple breast lumps was referred to a local Breast Clinic. She had malignant melanoma of the left middle finger and amputation had been performed 3 months earlier. Fine needle aspiration was performed on two of the breast lumps and they were diagnosed as melanotic melanoma. The pleomorphic malignant cells were immunoreactive for S100 protein and HMB 45. Ultrasound (US) was later performed which showed more than five well circumscribed hypoechoic masses, ranging in size from 0.5 to 1.5 cm, in both breasts. Mammography was performed, which showed three medium density well circumscribed masses in the right breast. There was no axillary adenopathy. Magnetic resonance imaging (MRI) of both breasts was performed with a 1.5T superconductive MR imager (Signa Advantage, GE Medical Systems, Milwaukee, U.S.A.) and a bilateral phased array breast coil. Pre-contrast medium axial T1-weighted spin-echo (TR/TE 1⁄4 500/12) with fat saturation and sagittal T2-weighted fast spin-echo (TR/TE 1⁄4 3440/126, ETL 1⁄4 12) images were acquired with 4 mm thick sections, 1 mm gap, a 256 × 192 matrix and two excitations. After intravenous administration of gadopentetate dimeglumine (0.2 mmol/kg), fat-suppressed axial T1-weighted spinecho images were taken. There were more than five abnormal masses in both breasts, ranging in size from 0.5 to 1.5 cm. The masses yielded high signal on T1-weighted (Fig. 1), low signal on T2-weighted (Fig. 2) and showed decreased signal intensity after contrast medium injection (Fig. 3). In the clinical work-up, there was no evidence of other metastases. Bilateral mastectomy was performed. A specimen photograph was taken (Fig. 4) and MRI was performed (Fig. 5). The patient was followed-up in the Breast Clinic.