This article discusses the rare occurrence of a sarcoid-like mediastinal reaction in the context of histiocytic sarcoma. The case study involves a 47-year-old male who presented with a solid lump in his hand, which was later diagnosed as histiocytic sarcoma. Further imaging and biopsies revealed multilevel mediastinal adenopathies suggestive of malignancy, but subsequent tests confirmed a sarcoid-like reaction instead. The article emphasizes the importance of considering sarcoid-like reactions in the differential diagnosis of patients with sarcoma and lung non-caseating granulomas. [Extracted from the article]