Rhabdomyosarcoma of the breast.

Aim: The aim of this study was to describe the first imaging studies of a primary embryonal rhabdomyosarcoma of the breast in an adult woman.

Patient: This 45-year-old woman was seen for investigation of a palpable mass in the left breast. Examinations included mammography, Doppler ultrasound, and MRI. The diagnosis was made after surgical biopsy. Treatment consisted in neoadjuvant chemotherapy, followed by quadrantectomy and interstitial curietherapy. Imaging studies were performed both prior to and during therapy (i.e., after three then after six courses of chemotherapy). Imaging findings were correlated with histopathological findings.

Results: Mammography was not very contributive as the breasts were dense, particularly in the external left quadrants. On ultrasound, the mass had a tissue density and sharp contours; the mass was not highly vascularized on Doppler. MRI revealed a mass that enhanced markedly on both early and late contrast-enhanced T1-weighted sequences and was hyperintense on T2-weighted sequences. MRI appeared to be the best technique for the evaluation of the residual tissue.

Conclusion: Rhabdomyosarcoma is a rare tumor in adults; to our knowledge, this is the first report describing the imaging features and value of MRI for the work-up and follow-up of mammary rhabdomyosarcoma.