Despite its infrequent occurrence, the possible development of lymphoma or lymphoid lung disease in patients with Sjögren's syndrome should always be borne in mind. We describe a case of bronchus-associated lymphoid tissue (BALT) lymphoma in a patient with Sjögren's syndrome that clearly exemplifies the wide-ranging problems of diagnosing, treating and following such patients. This difficulty is due to the fact that the clinical and radiological findings suggest interstitial lung disease, and histological assays are required for a correct diagnosis. A precise knowledge of the various histological and radiological patterns of lung involvement can aid patient management.