Pulmonary MALT lymphoma with amyloid production in a patient with primary Sjögren's syndrome.

A 53-year-old woman was admitted to our hospital complaining of cough, low grade fever, chest pain and sicca symptoms. A chest radiograph showed an abnormal shadow and chest computed tomography revealed a tumor in left S6. She was diagnosed as Sjögren's syndrome by sialography and histological findings of labial biopsy. The surgically resected tumor specimen showed proliferation of lymphoid cells with lymphoepithelial lesions, which were positive for CD20 and kappa light chain. Kappa light chain-positive amyloid was found within the tumor. The tumor showed rearranged kappa light chain genes. The diagnosis was pulmonary mucosa associated lymphoid tissue lymphoma with amyloid production.