Sjögren’s syndrome as a cause of both lymphoid interstitial pneumonia and light chain deposition disease in a single patient

A man in his 70s presents with 12 months of progressive dyspnoea, sicca symptoms and Raynaud’s phenomenon. Serological testing and tear duct biopsy confirm Sjögren’s syndrome (SS). Bilateral nodular-cystic appearances highly suggestive of lymphoid interstitial pneumonia (LIP) are noted on high-resolution computed tomography (HRCT), supported by a 40% lymphocytosis on bronchoalveolar lavage. Biopsy of a non-characteristic additional pulmonary nodule diagnoses light chain deposition disease (LCDD). Extrapulmonary organ involvement is excluded. Pulmonary function tests are well-preserved, and the patient is kept under active surveillance without requiring immunomodulatory treatment. LIP and LCDD both have a strong association with SS. Identification of these disease associations is crucial as they may result in multiorgan involvement or progression to haematological malignancy. This is the first case published in the literature and highlights that a pragmatic approach to investigations can avoid unnecessary procedures, and that treatment may be guided by symptomology.