HRCT in primary pulmonary lymphoma: can CT imaging phenotypes

Primary pulmonary lymphoma (PPL) is defined as clonal lymphoid proliferation involving lung parenchyma and/or bronchi without detectable extra pulmonary lymphoma at primary diagnosis or the subsequent 3 months (1). PPL is a rare neoplasm, accounting for ≤1% of all lymphomas and 0.5–1% of primary pulmonary malignancies (2). The most common type of PPL is mucosa-associated lymphoid tissue (MALT) lymphoma (70–90%) (3), which is also called extranodal marginal zone B cell lymphoma. It can arise from any mucosal site. However, lung is the most common organ involved especially MALT of the bronchus. The second most frequent histological type of PPL is diffuse large B-cell lymphoma (DLBCL, 5–20%) (4). In 1963, Saltzstein (5) was the first to report a large number of PPLs, since then, a variety of studies have reported the different subtypes of PPL. While the majority focused on MALToma, few have reported on other histological phenotypes of PPL