Nodular Amyloidoma and Primary Pulmonary Lymphoma with Amyloid Production: A Differential Diagnostic Problem

Abstract

Nodular amyloidomas (NA) of the lung are nonneoplastic inflammatory nodules containing eosinophilic amyloid deposits and a lymphoplasmacytic infiltrate. In some instances, the extensive amyloid deposits may obscure an underlying lymphoproliferative disorder. The histologic and immunohistologic features that discriminate these two differential diagnostic possibilities were studied in this series of six cases of NA and five cases of primary low-grade malignant lymphomas of lung with secondary amyloid deposits (ML). Two of lymphoma cases showed histopathologic and immunophenotypic features of B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma (B-cell CLL/SLL), and three cases were low-grade B-cell lymphoma derived from mucosa associated lymphoid tissue (MALT lymphoma). Key discriminating morphologic features between NA and ML included lymphatic tracking of the cellular infiltrate (3/5 ML; 1/6 NA), pleural infiltration (3/5 ML; 0/6 NA), sheet-like masses of plasma cells (5/5 ML; 0/6 NA) and reactive follicles (4/5 ML; 1/6 NA). Lesional circumscription, vascular and bronchial destruction, lymphoepithelial lesions, and granulomas were not helpful discriminators. Immunohistochemical features indicating a dominant CD20؉, CD79a؉ B-cell population (5/5 ML; 0/6 NA), light chain restriction (4/5 ML; 0/6 NA), and aberrant antigen expression of CD20/CD43 (2/5 ML; 0/6 NA) were helpful. Amyloid tumors with a reactive lymphoplasmacytic infiltrate can be separated from low-grade malignant lymphomas utilizing both histologic and immunohistochemical features.

Two cases of monoclonal nodular pulmonary amyloidosis and review of the literature

“…Particularly of the popyclonal type, approximately one hundred cases have been reported in the literature of NPA (Table 1). 3,[5][6][7][8][9][10][11][12][13][14][15][16][17] NPA is typically of the AL variant, specifically lambda light chain despite the usual association of AL amyloid with systemic amyloidosis. [2][3][4]15 The amyloid is speculated to arise from a reaction to chronic inflammatory conditions of the lung, including connective tissue disorders, tuberculosis, or HIV infection.…”

A 70-Year-Old Man With Large Cervical and Mediastinal Lymphadenopathies

“…37 Amyloidomas consist of well-circumscribed dense amorphous eosinophilic amyloid protein, surrounded by an infl ammatory cell infi ltrate that consists of plasma cells and lymphocytes with an occasional granulomatous reaction. 38 Th e type of amyloidosis is determined by immunohistochemical staining of the biopsy specimen. k or L chains on immunofl uorescence microscopy are seen in AL amyloidosis.…”

Amyloidosis of the Lung

“…44 In the past, nodular pulmonary amyloidosis and primary pulmonary lymphoma with amyloid production were thought to be 2 fundamentally different processes. 45,46 However, many experts now believe that most cases of nodular pulmonary amyloidosis are the result of an underlying lymphoproliferative disorder in the spectrum of extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). 33 The underlying lymphoproliferative disorder might be subtle, but sensitive methods reveal a clonal B-cell population in most cases.…”