Inflammatory pseudotumors of lymph node origin show macrophage- derived spindle cells and lymphocyte-derived cytokine transcripts without evidence of T-cell receptor gene rearrangements. Implications for pathogenesis and classification as an idiopathic retroperitoneal fibrosis-like sclerosing immune reaction.
Sclerosing pseudotumorous immune reactions of the retroperitoneum have been shown to consist of HLA-DR-positive spindle-shaped fibroblasts and macrophages that resemble fibroblasts, and in some instances they contain clonal populations of T lymphocytes not found in granulation tissue, keloids, nodular fasciitis, or fibromatoses. In patients who are iatrogenically immunosuppressed, circulating monocytes may be induced in vitro to transform into spindle-shaped macrophages, and secrete collagen after stimulation by conditioning medium from activated T lymphocytes. The authors investigated a series of five inflammatory pseudotumors (IPT) of lymph node origin for identification of spindle-shaped macrophages, T-cell receptor gene rearrangements, and lymphocyte-derived cytokine mRNA production. All cases of IPT demonstrated spindle-shaped macrophages resembling fibroblasts or myofibroblasts characterized by vimentin, CD45 (LCA), CD68 (KP1) or HAM-56, and HLA-DR(LN3) immunoreactivity and demonstrated production of procollagen-alpha1 (I) mRNA by in situ hybridization. Clonal T-cell receptor chain gene rearrangements were undetectable by polymerase chain reaction. Strong specific lymphocyte-derived interleukin-1beta and interleukin-6 mRNA cytokine transcripts were identified. Although all patients with IPT were managed with steroids and nonsteroidal anti-inflammatory medication, some had treatment-refractory disease. Because all-trans retinoic acid has been demonstrated to inhibit the in vitro transformation of monocytes into collagen-producing spindle-shaped macrophages ("neofibroblasts"), it may be of benefit for patients with IPT.
Menke
D M
DM
Department of Pathology, Mayo Clinic Jacksonville, Florida 32224, USA.
Griesser
H
H
Araujo
I
I
Foss
H D
HD
Herbst
H
H
Banks
P M
PM
Stein
H
H
D015703:Antigens, CD / Q000032:analysis; D001808:Blood Vessels / Q000473:pathology; D016207:Cytokines / Q000096:biosynthesis*; D015329:Gene Rearrangement, T-Lymphocyte; D006104:Granuloma, Plasma Cell / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D017403:In Situ Hybridization; D008198:Lymph Nodes / Q000473:pathology*; D008214:Lymphocytes / Q000276:immunology*; D008264:Macrophages / Q000473:pathology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D012185:Retroperitoneal Fibrosis / Q000276:immunology / Q000473:pathology; D012189:Retrospective Studies; D013154:Spleen / Q000473:pathology
D015703:Antigens, CD; D016207:Cytokines; D012333:RNA, Messenger