Two surgical cases of thymic MALT lymphoma associated with multiple lung cysts: possible association with Sjögren's syndrome.

Thymic mucosa-associated lymphoid tissue (MALT) lymphoma is rare. Sjögren's syndrome (SjS) has strong association with thymic MALT lymphoma but the exact etiology is unknown. On the other hand, SjS is characterized by the complication of various lung manifestations, including lung cysts. The mechanism for these lesions is also unknown. But the underlying SjS could result in MALT lymphoma with lung cysts. Herein, we demonstrate two surgical cases of thymic MALT lymphoma associated with multiple lung cysts and the characterization of this rare tumor. During surgery, the tumors were found to be well capsuled and had no adhesion or invasion to the surrounding tissues consistent with its characteristics of low grade malignancy. When thymic MALT lymphoma is suspected clinically, video-assisted thoracoscopic surgery might be the best approach for diagnosis. We propose that radiological findings of a thymic tumor along with lung cysts are an indication of thymic MALT lymphoma.