Adenoid cystic carcinoma of the breast: case report of a rare tumor with a good prognosis

Objective: The aim of this study was to report a case of a rare breast cancer subtype. Methodology: This is a case report. Results: This is a case of a patient diagnosed with adenoid cystic carcinoma of the right breast in June 2007, at 38 years of age. She underwent a quadrantectomy with right axillary lymph node dissection on September 14, 2007, followed by adjuvant radiotherapy, and remained under follow-up. In April 2019, probable recurrence was evidenced in the bone (L1) and lung. Bone biopsy in April 2019 did not show malignancy. Lobectomy in August 2019 confirmed metastasis of adenoid cystic carcinoma to the lung, with clear margins. She was referred for radiotherapy in L1 – 10 fractions were performed. In 2020, a nodule was found in the left kidney. A follow-up was proposed. In February 2021, there was new bone progression (osteolytic lesion in L1 and D6 with pathological fracture and pain). She was evaluated by neurosurgery, without surgical intervention. New radiotherapy was recommended. She underwent a video-assisted partial nephrectomy in October 2021, confirming adenoid cystic carcinoma. The patient is currently under follow-up and without evidence of oncologic disease. Conclusion: Therefore, this patient was diagnosed with adenoid cystic carcinoma of the right breast in 2007 (17 years of follow-up) and experienced disease recurrence in 2019. Metastasectomies of pulmonary and renal nodules were performed, as well as radiotherapy for bone metastases. She is currently under clinical follow-up with no signs of new lesions or indication for systemic treatment. The patient is asymptomatic with preserved functionality and quality of life.