Mesenteric rheumatoid nodules masquerading as an intra-abdominal malignancy: a case report and review of the literature

<p>Abstract</p> <p>Background</p> <p>Rheumatoid nodules are the most common extra-articular findings in patients with rheumatoid arthritis. They occur most commonly at pressure points such as the extensor surfaces of the forearms, fingers, and occiput, but have also been reported to occur in unusual locations including the central nervous system, pericardium, pleura, and sclera. We present the unusual case of rheumatoid nodules in the small bowel mesentery masquerading as an intra-abdominal malignancy.</p> <p>Case presentation</p> <p>A 65-year-old-male with a known history of longstanding erosive, nodular, seropositive rheumatoid arthritis was incidentally found to have a mesenteric mass on computed tomography (CT) exam of the abdomen. This mass had not been present on prior imaging studies and was worrisome for a malignancy. Attempts at noninvasive biopsy were nondiagnostic but consistent with a "spindle" cell neoplasm. Laparotomy revealed extensive thickening and fibrosis of the small bowel mesentery along with large, firm nodules throughout the mesentery. A limited bowel resection including a large, partially obstructing, nodule was performed. Pathology was consistent with an unusual presentation of rheumatoid nodules in the mesentery of the small bowel.</p> <p>Conclusion</p> <p>Rheumatoid nodules should be considered in the differential diagnosis of a patient who presents with an intra-abdominal mass and a history of rheumatoid arthritis. Currently, no tests or imaging modality can discriminate with sufficient accuracy to rule out a malignancy in this difficult diagnostic delimma. Hopefully, this case will serve as impetus for further study and biomarker discovery to allow for improved diagnostic power.</p

Cartilage oligomeric matrix protein in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive and life threatening disease with median survival of 2.5-3 years. The IPF lung is characterized by abnormal lung remodeling, epithelial cell hyperplasia, myofibroblast foci formation, and extracellular matrix deposition. Analysis of gene expression microarray data revealed that cartilage oligomeric matrix protein (COMP), a non-collagenous extracellular matrix protein is among the most significantly up-regulated genes (Fold change 13, p-value <0.05) in IPF lungs. This finding was confirmed at the mRNA level by nCounter® expression analysis in additional 115 IPF lungs and 154 control lungs as well as at the protein level by western blot analysis. Immunohistochemical analysis revealed that COMP was expressed in dense fibrotic regions of IPF lungs and co-localized with vimentin and around pSMAD3 expressing cells. Stimulation of normal human lung fibroblasts with TGF-β1 induced an increase in COMP mRNA and protein expression. Silencing COMP in normal human lung fibroblasts significantly inhibited cell proliferation and negatively impacted the effects of TGF-β1 on COL1A1 and PAI1. COMP protein concentration measured by ELISA assay was significantly increased in serum of IPF patients compared to controls. Analysis of serum COMP concentrations in 23 patients who had prospective blood draws revealed that COMP levels increased in a time dependent fashion and correlated with declines in force vital capacity (FVC). Taken together, our results should encourage more research into the potential use of COMP as a biomarker for disease activity and TGF-β1 activity in patients with IPF. Hence, studies that explore modalities that affect COMP expression, alleviate extracellular matrix rigidity and lung restriction in IPF and interfere with the amplification of TGF-β1 signaling should be persuaded. © 2013 Vuga et al