INTRODUCTION: Lupus Mastitis is an unusual presentation, about 2% to 3% of lupus erythematosus deep or lupus panniculitis, a rare variant of lupus erythematosus characterized by inflammation of the subcutaneous tissue. REPORT: Woman, 27 years old, referred to the outpatient mastology by bilateral breast pain, more pronounced at right. For four years she has been feeling pain like stabbing, intermittent, without irradiation, compounded with the mobilization of the upper and relief with rest and worsened in the last year. Medical history: no personal history of breast pathologies. Diagnosis of lupus erythematosus two years ago. At 12 years old presented sudden dyspnea with strong intensity, accompanied by widespread muscle pain, episodic, recurrent, with periods of spontaneous remission without regular medical monitoring. At 23 years old, she had a worsening of health and new symptoms such as abdominal pain, joint pain, muscle pain, mammary pain, diarrhea, vomiting, night sweats, nodules in the body, mouth and nose ulcers, leading to hospitalizations. During the hospitalization realized several tests, including: abdominal ultrasound revealed increased echogenicity of the skin, a transesophageal echocardiogram showed pulmonary hypertension, right chamber overload, patent foramen ovale and minimal pericardial effusion as confirmed by cardiac catheterization. Research results for autoimmune diseases. showed: ANA speckled pattern 1/1. 280; + Anti-Ro and anti-Scl 70 +. For investigation of breast tenderness and bilateral thickening, performs breast ultrasound reveals multiple nodules, mainly in the upper quadrants bilaterally, complemented by mammography wich showed coarse calcifications in form of serpent and nodular, dispersed bilaterally. Classified as BIRADS II. Start treatment with hydroxychloroquine, prednisone and diclofenac, have discharged with complete improvement of dyspnea. The following regular treatment with a rheumatologist. The physical examination of the breasts wich showed large-volume breasts, pendulous, with streaks bilateral bulging of the medial upper quadrant of the right breast that exacerbates the dynamic inspection. Palpation: Right breast: an area extremely dense, irregular, painful, in measuring 5x5cm mainly in medial upper quadrant Left breast: diffuse dense areas, especially in the upper outer quadrant.. Regional lymph nodes, no palpable. DISCUSSION: Coarse calcifications showed in the patient s mammogram, are probably due to the final stage of fat necrosis. The histological diagnosis can be difficult because fibrosis and calcification are the main findings. A biopsy may aggravate the situation. Thus it is possible to base the diagnosis on radiological findings and previous diagnosis of lupus. Treatment of Lupus mastitis not different from the treatment of lupus erythematosus, and the glucocorticoid and hydroxychloroquine the main drug.