Primary pulmonary lymphoma: a re‐appraisal of its histogenesis and its relationship to pseudolymphoma and lymphoid interstitial pneumonia

Abstract

The clinical, morphological and immunohistochemical features of 15 cases of pulmonary lymphoproliferative disease are described. The diagnosis of primary pulmonary lymphoma was based in 13 cases on the demonstration of light chain restriction and in two cases on morphological characteristics. Many patients had a prolonged clinical course without significant clinical or radiographic deterioration, a feature associated with malignant lymphomas of mucosa-associated lymphoid tissue in other sites. Lymphoepithelial lesions were characteristic and malignant cells had the features of centrocyte-like cells, similar to those described in gastric and salivary gland lymphomas. Germinal centres were present in three cases: some were partially overgrown by centrocyte-like cells but residual polyclonal follicle centre cells and dendritic reticulum cells were still detectable. It is suggested that primary pulmonary lymphoma arises from centrocyte-like cells normally present in bronchus-associated lymphoid tissue. In addition to the malignant population, reactive follicles and polytypic plasma cells are frequently present and may prejudice interpretation of immunohistochemical features. In the light of these findings, cases previously diagnosed as pseudolymphoma or lymphoid interstitial pneumonia require careful assessment and the majority are, in reality, examples of primary pulmonary lymphomas.

Radiological appearances of lymphomas arising from mucosa-associated lymphoid tissue (MALT) in the lung

“…If the consolidation appears diffuse, a feature which has previously been called LIP (Fig. 3), it is likely to reflect parenchymal extension of MALT lymphoma from peribronchial/peribronchiolar regions [6]. There appears to be no lobar predilection and air bronchograms are a well recognized feature, particularly on CT, irrespective of pattern or distribution of tumour.…”

“…He did, however, warn that histological differentiation between a malignant lymphoma and pseudolymphoma was not always possible. Since then, the introduction of immunohistochemical and molecular genetic methods has confirmed that most of these tumours are, in fact, low-grade monoclonal B-cell lymphomas [5][6][7][8].…”

“…The presence of reactive follicles and plasma cells within MALT lymphoma masses, in addition to the monoclonal malignant population, may have caused their overdiagnosis as benign lymphoid proliferations on the basis of apparent polyclonality [6]. Immunohistochemical methods for the detection of surface immunoglobulin using frozen tissue or fresh cell suspensions are more sensitive, allowing turnouts to be diagnosed more accurately if such material is available [6]. Some groups have reported gene rearrangement studies as useful in the distinction of pseudolymphoma from lymphoma [21,22].…”

Primary Pulmonary Extranodal Marginal Zone Lymphoma: An Atypical Radiological Pattern

“…Immunohistochemical staining is essential for certain diagnosis. Especially when the biopsy specimen is small, alternatives such as diffuse lymphoid hyperplasia, interstitial lymphoid pneumonia, and follicular bronchitis must be considered (15). Bone marrow involvement is mostly seen with nodal or splenic MZL.…”

Lymphoproliferative lung disorders: clinicopathological aspects

“…The authors also concluded that the majority of neoplasms with a low-grade cytological appearance should be considered as reactive proliferations, introducing the term ''pseudolymphoma''. This hypothesis showed significant weak points and, approximately 20 years later, ADDIS et al [3] concluded that ''most if not all the cases of pseudo-lymphoma can be classified, when re-evaluated, as malignant lymphoma''. Knowledge of these entities expanded rapidly after the advent of new investigative tools such as immunohistochemistry and molecular biology techniques.…”