Pulmonary and thymic lymphoid hyperplasia in primary Sjögren's syndrome

Pulmonary and thymic lymphoid hyperplasia with characteristic clinicoradiological manifestations were seen in a 71-year-old woman who was diagnosed with primary Sjögren's syndrome. A hazy opacity 12 mm in diameter and an anterior mediastinal nodule 20 mm in diameter were incidentally detected on computed tomography. Thoracoscopic biopsy revealed lymphoid hyperplasia in the lung accompanying thymic lymphoid hyperplasia. Immunohistochemically, the pulmonary lesion was considered to be nodular lymphoid hyperplasia (NLH), not lymphoma. A previously undescribed finding in the NLH was the hazy opacity containing an air bronchiologram, not a solid nodule. This finding might suggest a common causal relation for NLH, thymic hyperplasia, and primary Sjögren's syndrome.