[Mucosa-associated lymphoid tissue lymphoma; report of two cases].

Primary pulmonary malignant lymphoma is a rare disease that is thought to belong to a category of malignant lymphomas arising from mucosa-associated lymphoid tissue (MALT). We presented 2 cases of MALT lymphoma. Case 1: In a 39-year-old woman, an abnormal shadow was detected in chest radiography in the left S3. The diagnosis was organizing pneumonia in consequence of the further examination. One year after an growing abnormal shadow was detected again, we performed the tumor resection with the thoracoscopy in the possibility of malignancy. The pathological diagnosis was MALT lymphoma. Case 2: In a 70-year-old man, middle lobe syndrome was detected in chest radiography. As a result of the bronchial biopsy, the lesion was suspected of MALT lymphoma. Right middle lobectomy was performed, and the tumor was diagnosed as a MALT lymphoma histologically. He underwent an effective postoperative radiotherapy and has had no evidence of recurrence.