Extramedullary paraspinal hematopoiesis in hereditary spherocytosis.

Extramedullary hematopoiesis is a rare condition, characterized by the appearance of hematopoietic elements outside the bone marrow. It occurs primarily in patients with chronic myeloproliferative disorder or congenital hemolytic anemia. We report on a 60-year-old man with hereditary spherocytosis who presented with an extramedullary paraspinal hematopoietic mass, splenomegaly, and bone marrow expansion in the right distal femur and proximal tibia metaphysis. The diagnosis was established after biopsy of the paravertebral mass. The patient underwent a splenectomy.