Ground-Glass Opacity in Lung Metastasis from Breast Cancer: A Case Report
A 43-year-old woman was referred to our clinic with fever and persistent cough and sputum for two weeks. She had been diagnosed with breast cancer (invasive ductal carcinoma, estrogen receptor negative, progesterone receptor negative, and human epidermal growth factor receptor 2 negative, cT2N2M0, stage IIB) with axillary lymph node metastasis three months prior to presentation and was on neoadjuvant chemotherapy. After completing four cycles of AC chemotherapy (doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2 on day 1 every three weeks), she was currently on the second cycle of docetaxel/S-1 chemotherapy (docetaxel 75 mg/m2 and S-1 30 mg/m2 twice daily for 14 days every three weeks) as part of a clinical trial at our institution. It was her ninth day of chemotherapy when she visited the clinic. The patient, a non-smoker with no known allergies, had no other past medical history, and denied hazardous substance exposure or recent travel.\nShe complained of cough with sputum production and mild dyspnea. She had a low-grade fever of 37.7℃ and breath sounds were almost silent on auscultation. The chest radiograph showed a suspicious consolidation in the right upper lung field and diffuse bilateral haziness (). Laboratory data revealed no leukocytosis (white blood cell [WBC] count, 5,590/µL), serum chemistry values were within normal limits, and C-reactive protein was elevated (221.18 mg/L). High-resolution chest CT showed patchy consolidations and GGO in the subpleural area of both upper lobes and diffuse GGO bilaterally in the lower lobes (). The primary tumor in the left breast remained stable and the metastatic lymph node in the left axilla seemed to be decreased in size after the aforementioned six cycles of chemotherapy.\nInitially, she was thought to have bacterial or viral pneumonia, given immunosuppression from chemotherapy, or drug-related interstitial pneumonitis, and was treated with antibiotics for three weeks. However, the bilateral lung GGO showed no change on serial follow-up CT scans. Fiberoptic bronchoscopy was done and bronchoalveolar lavage fluid from the right upper lobe was sent for analysis. It contained 1,000 WBCs/mL with 98% macrophages and 2% lymphocytes. Cultures revealed no specific pathogen, and cytology showed no evidence of malignant cells. After empiric treatment with steroids (35 mg of prednisolone) for seven days, her symptoms showed mild improvement, but the diffuse infiltrative lung lesions remained unchanged.\nWhile she was being treated for suspected interstitial pneumonia and with the chemotherapy delayed, changes in the skin color of the breast were observed. Considered to be a clinical sign of disease progression, neoadjuvant chemotherapy was stopped after six cycles out of the initially-planned eight and she dropped out of the clinical trial. Magnetic resonance imaging of the breast showed no change in the maximum extent of the primary tumor in the left breast and the metastatic lymph node in the left axilla, but showed an increase in size of the subareolar mass with breast contraction, suggesting disease progression. Thus, she underwent modified radical mastectomy and axillary lymph node dissection for the underlying breast cancer, and thoracoscopic lung biopsy of the right upper lobe and right middle lobe was performed concurrently for the pathologic diagnosis of lung involvement. Postoperative pathology of the lung revealed metastatic carcinoma from the breast, predominantly in the lymphovascular spaces (). Diagnosed with breast cancer with lung metastasis, she is currently undergoing palliative chemotherapy.