Extranodal Marginal Zone Lymphoma of the Lung: Evolution from an Underlying Reactive Lymphoproliferative Disorder

Abstract

Extranodal Marginal Zone Lymphoma (ENMZL) of Mucosa-Associated Lymphoid Tissue (MALT) is a problematic and sometimes controversial diagnosis. While commonly seen in the stomach in the setting of chronic Helicobacter pylori infection, other extranodal sites, such as the lung, may also present with disease. ENMZL is clinically and morphologically heterogeneous; however, regardless of presentation, the etiology lies in the accumulation of lymphoid tissue in non-traditional sites. This phenomenon is typically secondary to an underlying inflammatory stimulus such as chronic infection or autoimmune states. The current case report details the clinical history of a patient with Sjögren syndrome over a four year period who eventually developed ENMZL. The patient initially presented with an atypical, but polyclonal, lymphoproliferative process diagnosed as lymphocytic interstitial pneumonia. Over time, the patient showed evolution to a monoclonal process with associated radiologic progression of disease. This evolution manifested as a dense lymphoid infiltrate with prominent plasmacytic differentiation and the development of a lung mass radiologically. This case contributes to the growing body of knowledge that suggests ENMZL lies along a biological spectrum of lymphoproliferative disorders whereby a benign, reactive process may eventually undergo malignant transformation. This evolution likely represents the acquisition of genetic abnormalities that allow autonomous proliferation in the absence of the initial immune stimulus. In practice, determining when this event occurs and, thus, distinguishing between reactive and neoplastic disorders within this spectrum may be difficult as no single clinicopathologic feature may be present to establish the diagnosis. This case further illustrates the importance of correlating the clinical, radiologic and pathologic data to evaluate patients with atypical pulmonary lymphoproliferative disorders and to allow the optimal management of their disease.

The spectrum of MALT lymphoma at different sites: biological and therapeutic relevance

“…103 Moreover, a previous history of lymphocytic interstitial pneumonia, which is frequently associated with autoimmune disorders, or of other rare nonneoplastic pulmonary lymphoid proliferations (follicular bronchiolitis and nodular lymphoid hyperplasia) support the concept that lymphoma may also evolve from these noninfectious inflammatory processes. 104 …”

MALT lymphoma arising on a background of reactive pulmonary lymphoid hyperplasia in a patient with systemic lupus erythematosus

“…Interstitial lung diseases are frequently complicated by development of malignancies, and while most cases are carcinomas, rare cases of lymphoma have been reported, these being diffuse large B cell lymphomas and often associated with connective tissue disorders (CTDs). Reactive pulmonary lymphoid hyperplasia (RPLH), typically in the form of lymphoid interstitial pneumonia (LIP), often arises in patients with CTDs and only rarely shows malignant transformation, with many of the early putative cases of transformation to mucosa‐associated lymphoid tissue (MALT) lymphoma from LIP being lymphoma de novo . Herein we present a case of pulmonary non‐Hodgkin lymphoma of MALT origin arising on a background RPLH with co‐existent amyloidosis, confirmed by immunohistochemical and clonality studies.…”

Extranodal localization of non-Hodgkin’s lymphoma in systemic sclerosis: A diagnostic challenge and review of the literature

“…Marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) is a B-cell neoplasm and type of indolent NHL. Extranodal marginal zone lymphoma may occur in many different sites, 8 but lung represents an uncommon site. 9…”