title: Primary pulmonary low-grade marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type with prominent hyalinosis. A case report.
abstract: We report a case of primary pulmonary low-grade marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT)-type with prominent sclerosis, which morphologically resembled pulmonary hyalinizing granuloma (PHG) or inflammatory pseudotumor (IPT) of the lung. The patient, a 66-year-old Japanese female with a history of Sjögren's syndrome and primary biliary cirrhosis, presented with a lower left lobe mass 6.8 cm in diameter. Histologically, the lesion is characterized by dense bundles of collagen with scattered plasma cells, mature small lymphocytes, and histiocytes among the collagen bundles. Only the peripheral area of the nodule contained dense lymphoplasmacytoid and histiocytoid infiltrates. A few centrocyte-like cells were obscured by the numerous plasma cells and plasmacytoid cells. In addition, lymphoepithelial lesions and colonalized lymphoid follicles were identified by immunohistochemistry alone. Although PHG and IPT are unlikely to be confused with pulmonary MALT-type lymphomas, the present case suggests that MALT-type lymphoma should be added to the list of differential diagnoses for PHG and IPT.
authors.affiliation: Department of Pathology and Clinical Laboratories, Gunma Cancer Hospital, Ohta, Japan. mkojima@gunma-ccp.jp
authors.forename: Masaru
authors.initials: M
authors.lastname: Kojima
authors.forename: Shigeo
authors.initials: S
authors.lastname: Nakamura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ban
authors.forename: Masaharu
authors.initials: M
authors.lastname: Inagaki
authors.forename: Shiro
authors.initials: S
authors.lastname: Sugihara
authors.forename: Katsue
authors.initials: K
authors.lastname: Yoshida
authors.forename: Nobuhide
authors.initials: N
authors.lastname: Masawa
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D018572:Disease-Free Survival; D005260:Female; D015769:Granuloma, Respiratory Tract / Q000175:diagnosis; D006801:Humans; D006818:Hyalin / Q000378:metabolism; D008171:Lung Diseases / Q000175:diagnosis; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D018442:Lymphoma, B-Cell, Marginal Zone / Q000378:metabolism / Q000601:surgery; D016726:Plasma Cell Granuloma, Pulmonary / Q000175:diagnosis