Blueberry muffin baby: the pathogenesis of cutaneous extramedullary hematopoiesis

Two neonates exhibited the clinical picture of the "blueberry muffin baby" at delivery. The integument manifested petechiae and purpuric magenta-color ed macules, papules, and plaques,as well as, blueberry-colored ecchymoses. These findings led to the diagnosis of a connatal cytomegalovirus infection and fetal erythroblastosis, respectively. The hemorrhagic-purpuric looking skin lesions reflected extramedullary hematopoiesis with ultrastructural s tudy disclosing evidence of both erythro- and granulopoietic lineage. For t he first time, we were able to demonstrate that complexes of red cells in v arious stages of maturation can occur in the skin,similarly to, the erythro blastic islands of the bone marrow. In the pathogenesis of extramedullary h ematopoiesis, mechanisms underlying the reconstitution of blood cells must be considered. These may reactivate hematopoiesis in organs where it previo usly occurred in embryonic and fetal life. Possible causative factors may b e great compensatory demand, deficient replacement, or loss or dysfunction of corpuscular blood elements. This. would explain the occurrence of this d isease entity in conjunction with etiologically completely heterogeneous sy stemic diseases.