A Case of Pathological Complete Response and Resolution of Dermatomyositis Following Neoadjuvant Chemotherapy in HER2-Positive Early Breast Cancer.

INTRODUCTION: Dermatomyositis (DM) is an idiopathic inflammatory myopathy (IIM) mainly characterized by subacute muscle weakness and skin rash sometimes associated with malignancy.

CASE PRESENTATION: A 61-year-old female was admitted to our hospital because of progressive proximal muscular weakness, heliotropic rash and left breast rash. Muscle biopsy findings were consistent with dermatomyositis (DM). A full panel of myositis associated (MAA) and specific antibodies (MSA) revealed the presence of anti-nuclear antibodies (1:160, speckled), Anti-Ro52 and anti TIF1-γ antibodies. A whole body Computed Tomography Scan showed three left mammary nodules and homolateral axillary lymphadenopathy. The breast biopsy confirmed the diagnosis of ductal carcinoma. Patient was initiated to neoadjuvant chemotherapy followed by surgery for cancer, and corticosteroid and intravenous immunoglobulins for DM with a complete resolution of muscle weakness and pathological complete response of breast cancer. Discussion and conclusion. Similar cases in literature are commonly referred to a first-line surgery and the role of neoadjuvant chemotherapy is debatable.