From lymphocytic interstitial pneumonia to MALT lymphoma of lung: a case report with a 5-year diagnostic dilemma.

Lymphocytic interstitial pneumonia (LIP) and mucosa-associated lymphoid tissue (MALT) lymphoma of lung are all uncommon disorders of respiratory system. MALT lymphoma of lung is a distinct and unique subtype of marginal zone B-cell non-Hodgkin's lymphoma (NHL) characterized by malignant cells arising from extranodal sites. They are characteristic of exuberant lymphoid infiltration in pathological tissue. Therefore, in some cases, they are too similar in clinical manifestation, chest imaging and pathology to make differential diagnosis. Here, we report a 43-year-old woman who underwent a tough process for the final diagnosis. From this case, we could get a well understanding of difference between LIP and MALT lymphoma of lung.