“…The LIP pattern could be found in a broad range of clinical settings, including Legionella pneumonia and CTD-ILD (i.e., Sjögren's Syndrome, Rheumatoid Arthritis, Systemic Lupus Erythematosus), or associated with other systemic diseases (i.e., Hashimoto's Disease, Pernicious Anemia, Autoimmune Hemolytic Anemia, Primary Biliary Cirrhosis, Chronic Active Hepatitis, Myasthenia Gravis, Human Immunodeficiency Virus (HIV) Infection especially in children, Common Variable Immunodeficiency). Idiopathic cases are extremely rare [136][137][138][139][140][141][142][143][144][145][146][147]. A diffuse and dense cellular chronic interstitial infiltrate with a primarily alveolar septal distribution, composed of a mixture of mature plasma cells and polyclonal lymphocytes in varying proportions, is the histological hallmark of the LIP pattern (Figure 2F).…”