Endobronchial ultrasound-guided transbronchial needle aspiration facilitating diagnosis of sarcoidosis in a breast cancer patient with multiple lymphadenopathy: a case report

Background Sarcoidosis is a benign systemic granulomatous disorder of unknown etiology. Cell-mediated immunity disorder is often found in sarcoidosis patients, and an association between malignant tumors and sarcoidosis has been suggested. Sarcoidosis and malignant disease can occur simultaneously or sequentially, leading to misdiagnosis and mistreatment. Sarcoidosis is diagnosed clinically, radiologically, and histologically. We report herein a case of sarcoidosis diagnosed by endobronchial ultrasound-guided transbronchial needle aspiration from the mediastinal lymph nodes of a breast cancer patient. Case presentation The patient was a 70-year-old Asian woman who presented with right breast tumor. A 20-mm movable mass was identified in the inferolateral quadrant of the right breast, and mammography revealed a spiculated mass with calcification. Ultrasonography revealed a mass with internal hypoechogenicity, and biopsy revealed estrogen receptor-positive, human epidermal growth factor receptor 2-positive invasive ductal carcinoma. Positron emission tomography/computed tomography showed multiple lymphadenopathy including mediastinal lymph nodes, with fluorodeoxyglucose accumulation in those nodes suggesting breast cancer metastases. Endobronchial ultrasound-guided transbronchial needle aspiration of a mediastinal lymph node revealed noncaseous epithelioid granuloma. Due to a history of uveitis and elevated soluble interleukin 2 receptor, lymphadenopathy due to sarcoidosis and stage IIA breast cancer were diagnosed. Right partial mastectomy and axillary lymph node dissection were performed after preoperative chemotherapy. No exacerbation of sarcoidosis symptoms has been observed during treatment. Conclusion We report a case of breast cancer in which sarcoidosis could be diagnosed based on endobronchial ultrasound-guided transbronchial needle aspiration, a history of uveitis, and elevated soluble interleukin 2 receptor despite fluorodeoxyglucose positron emission tomography/computed tomography suggesting multiple lymph node metastases. This report emphasizes the importance of differential diagnosis of lymph node involvements in cancer patients.