Mucosa-associated Lymphoid Tissue Lymphoma of the Trachea in a Patient with Breast Cancer.

We herein report the case of a 93-year-old woman with breast cancer on the left side. Preoperative computed tomography of the chest showed irregularities and narrowing of the mid-trachea. Bronchoscopy was performed, and the results of a biopsy supported a diagnosis of mucosa-associated lymphoid tissue (MALT) lymphoma. The patient responded to treatment with prednisone alone, with a reduction in the size of the lesion. MALT lymphoma of the trachea is extremely rare, and there are only a few case reports of double cancer, i.e., MALT lymphoma of the trachea and breast cancer.