An intriguing case of a paravertebral extramedullary erythropoiesis presenting as tumor-mimicking lesion in a patient with eosinophilia with FIP1L1-PDGFRA rearrangement.

Extramedullary hematopoiesis in the posterior mediastinum is rare. Our case interested a 28-year-old man with a history of eosinophilia with FIP1L1-PDGFRA fusion gene who had a mediastinal mass surgically excised. Pathological examination concluded to an extramedullary erythropoiesis. This case is original by its location and the presence of only the erythroblastic line rearrangement.