Rationale:Most soft-tissue lesions in the hand and wrist have a benign etiology, and malignant tumors, such as soft-tissue sarcomas, are rare. Mimickers of soft tissue tumors in the hand and wrist are more common than true neoplastic lesions; however, soft tissue pseudotumors that mimic malignancy are very rare.Patient concerns:This study describes 2 patients with soft tissue pseudotumors of the hand and wrist. Both patients presented with rapidly growing soft-tissue masses. Magnetic resonance imaging (MRI) revealed ill-defined margins and an aggressive appearance in both cases, leading to a strong suspicion of malignant soft tissue tumors.Diagnosis:Both patients underwent incisional biopsies, and the final diagnoses were inflammation due to IgG4-related disease in the first case and chronic granulomatous inflammation in the second case.Interventions:The first patient was administered oral steroids, while the second patient was treated with anti-inflammatory drugs.Outcomes:Both patients showed a reduction in swelling of the hand and wrist.Lessons:Although the imaging approach for pseudotumorous lesions is similar to that for true soft tissue tumors, the management of these lesions is different. Biopsies should only be performed when the diagnosis is unclear.