A case of pulmonary primary MALT lymphoma with distinctive bronchoscopic findings.

Mucosa-associated lymphoid tissue (MALT) is a low-grade lymphoma, but cases in which it has transformed into a high-grade lymphoma have been reported, necessitating an accurate diagnosis. The patient was a 79-year-old nonsmoking Japanese female with history of ocular sarcoidosis. A computed tomography scan of her chest revealed a 35-mm nodule in the left S1 + 2, contiguous with the lymph nodes. Additional nodules were observed around the left B5 and B10a. Bronchoscopy revealed stenosis caused by a white, glossy, elevated lesion with angiogenesis at the orifice of the left upper lobe bronchus. The biopsy specimen demonstrated the dominance of lymphoid cells and tested positive for CD20, CD79a, Bcl-2, and IRTA-1, which is consistent with the findings in MALT lymphoma. Therefore, in the presence of multiple infiltrative shadows along the bronchi with glossy elevated lesions without necrosis on bronchoscopy, it is important to consider MALT lymphoma as a differential diagnosis.