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.