Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 0 0 2026 04 21 11326 11326 Fariba Abbasi Department of Pathology, Solid Tumor Research Center, Cellular and Molecular Medicine Institute, Urmia University of Medical Sciences, Urmia, Iran. َأَِAND Department of Pathology, Faculty of Medicine, Urmia University o Medical Sciences, Urmia, Iran. Ata Abbasi Department of Pathology, Faculty of Medicine, Urmia University o Medical Sciences, Urmia, Iran. AND Department of Pathology, Cellular and Molecular Research Center, Cellular and Molecular Medicine Institute, Urmia University of Medical Sciences, Urmia, Iran Mohammad Reza Pashaei Department of Gastroenterology, Patient Safety Research Center, Clinical Research Institute, Urmia University of Medical Sciences, Urmia, Iran. AND Department of Internal Medicine, Faculty of Medicine, Urmia University o Medical Sciences, Urmia, Iran. Khadijeh Azimi Department of Orthopedic, Khatamolanbia Hospital, Salmas, Iran. Pegah Saedifar Department of Pathology, Faculty of Medicine, Urmia University o Medical Sciences, Urmia, Iran. Amir Nezafat Department of Pathology, Faculty of Medicine, Urmia University o Medical Sciences, Urmia, Iran. 2024 10 30 2025 07 26 IgG4- related disease is a systemic fibroinflammatory syndrome characterized by tumefactive enlargement of  affected organ , diffuse lymphoplasma cells infiltration with a large number of  IgG4 producing plasma cells and  sclerotic changes. The most commonly involved  organs are pancreas, lacrimal and salivary glands. Patients show good  response to glucocorticoid therapy and despite its relapsing and remitting course, patients have good prognosis. We report an unusual presentation of IgG4- related  disease manifested as isolated soft tissue mass of hand which is an extremely rare manifestation of this disorder. https://acta.tums.ac.ir/index.php/acta/article/view/11326 https://acta.tums.ac.ir/index.php/acta/article/download/11326/6033