Transient dyserythropoiesis occurring during the involutionary phase of stage IV-S neuroblastoma.

An acutely ill 6-month-old female infant presented with massive hepatomegaly, accompanied by severe anemia with peripheral normoblastemia and thrombocytopenia. Bone marrow examination revealed erythroid hyperplasia with gross erythroid dysplasia, reduced granulocytic precursors, and virtually absent megakaryocytes. The bone marrow also contained completely necrotic cells occurring in clumps as well as singly. The appearances suggested bone marrow involvement by neuroblastoma. Accordingly, combination chemotherapy was instituted and laparotomy was performed as soon as her clinical condition had improved. Left adrenalectomy was carried out, because a small adrenal nodule of ganglioneuroma was present. Liver biopsy showed expansion of portal tracts by loose fibrous connective tissue containing hemosiderin deposits and some degenerate cellular debris, consistent with areas of involuted metastatic neuroblastoma. Complete recovery followed, and subsequent bone marrow examination was entirely normal. It is thought that the dyserythropoiesis probably resulted from the release of toxic metabolites from regressing neuroblastoma.