Lymphocytic interstitial pneumonitis (LIP) in Sjögren's syndrome: a case report and a review of the literature.

Sjõgren's disease is one of the most common rheumatological diseases and can present with a variety of extra-glandular manifestations. Lymphocytic Interstitial Pneumonitis (LIP) is the most common lung pathology in these patients. It is important to know and recognize this condition because it is potentially treatable. It is also frequently misdiagnosed and treated as infectious pneumonia multiple times before the correct diagnosis is made. It is a benign lymphoproliferative disorder characterized histologically by interstitial infiltration with polyclonal lymphocytes and plasma cells. High-resolution CT scan of the lungs shows extensive areas of ground-glass attenuation and interlobular septal thickening with scattered thin-walled cysts. An open-lung biopsy is the best method of diagnosing this condition, as less invasive techniques do not provide an adequate tissue specimen. LIP occurs in a wide variety of settings such as autoimmune disease, HIV disease, and as an adverse reaction to some medications; it is, therefore, considered to be a nonspecific response to many stimuli. The treatment usually consists of corticosteroids and other immunosuppressants, though there have been no controlled trials to date. Establishment of a registry may help better evaluate and treat this disease. We present the case of a patient who was diagnosed with LIP secondary to Sjögren's syndrome and also review the literature available.