Pulmonary amyloidosis in Sjogren's syndrome: a case report and systematic review of the literature.

Amyloidosis is a heterogeneous group of disorders characterized by misfolding of extracellular proteins. The two most common forms are light-chain (AL) and reactive (AA) amyloidosis. Pulmonary amyloidosis secondary to Sjogren's syndrome (SS) is rare, and there is a paucity of data on its clinical and radiological features. We describe the case of a 41-year-old woman with diffuse septal pulmonary AL (lambda) amyloidosis related to SS, in the absence of systemic amyloidosis. A systematic search for pulmonary amyloidosis in SS yielded 37 cases. Amyloidosis occurred almost exclusively in women (96.5%). Cough and dyspnoea (56%) were the most common symptoms. The diagnosis of pulmonary amyloidosis was made subsequent to that of SS, with a median delay of 7 years. Radiologically, diffuse nodules with (45.5%) or without (33.3%) multiple cysts were the most common pattern. Most cases were related to nodular AL amyloidosis (both kappa and lambda). Diffuse septal AA amyloidosis has been reported in SS. The index patient is the first documented case of diffuse septal pulmonary AL amyloidosis in SS, without systemic amyloidosis. Surgical lung biopsy (78%) is usually required to establish the diagnosis and rule out lymphoma. There is no data to support any definitive therapeutic intervention for SS-related pulmonary amyloidosis. Observation is sufficient for nodular amyloidosis. Further studies are necessary to assess the efficacy of current therapies in diffuse septal amyloidosis secondary to SS.