Lymphocytic interstitial pneumonia (LIP), one of the rarest forms of interstitial lung disease (ILD), shares manifestations with a variety of other diseases, making it difficult to diagnose. Because patients with LIP respond well to steroid treatment, it is important to exclude other diseases to achieve a reliable diagnosis of LIP.
In the recent study “Case-based discussion: Lymphocytic interstitial pneumonia a rare presentation in an immunocompetent adult male,” published in Lung India, researchers presented a case of LIP properly diagnosed and treated with steroids.
ILD is a heterogenenous group of more than 200 diseases of various causes, but with similar clinical, radiological, and histological features. ILDs of unknown cause, called idiopathic interstitial pneumonia (IIP), can be divided in three subgroups: the major IIPs that include idiopathic pulmonary fibrosis (IPF) and nonspecific interstitial pneumonia (NSIP); rare IIPs; and unclassified IIPs.
LIP, a benign lung lymphoproliferative disorder characterized by infiltration of inflammatory cells into the lung interstitium (tissue between the pulmonary alveoli and the bloodstream), is included in the group of rare IIPs. Although it is usually associated with systemic conditions or autoimmune diseases that include Sjogren’s syndrome, HIV or Epstein-Barr virus infection, some cases are idiopathic in nature (of unknown cause).
Diagnosis of LIP is made based on clinical and radiological findings, and then confirmed through lung biopsy and subsequent histological examination. Patients usually show persistent and progressive dry cough accompanied by shortness of breath and crackles. Radiological exams, such as chest X-rays and high-resolution computed tomography (HRCT) often show extensive fibrosis, opaque lung spots with ground glass appearance, and honey combing. In addition, bronchoalveolar lavage (washing of the lung) reveals lymphocyte infiltration.
However, LIP shares common manifestations with other diseases, including NSIP, hypersensitivity pneumonitis, usual interstitial pneumonia (UIP), cryptogenic organizing pneumonia (COP), lymphoma, and fungal and micobacterial lung infections.
In th study, the researchers report the case of a 24-year-old male who showed with a 3-month history of persistent dry cough and shortness of breath, for which antibiotics had been prescribed without any effects. Chest examination revealed crackles, but no evidence of Sjogrens syndrome or other autoimmune disease — which led to a suspicion of sarcoidosis and hypersensitivity pneumonitis.
The patients did not have any bacterial, fungal, or micobacterial lung infection, as assessed through sputum culture examination.
When radiology exams and lung biopsy were examined, the researchers excluded boncho-alveolar carcinoma and lymphoma, and found the common observations of LIP — which led to a diagnosis of LIP.
The patient was prescribed prednisolone, a steroid used to decrease the lymphocyte infiltration, with N-acetylcysteine, which is known to loosen the thick mucus in obstructive lung diseases. After six months of therapy, he was symptom-free with complete clearance on chest and radiological examination. Currently, he takes prednisolone 5 mg every two days and has no symptoms of LIP.