Secondary myelofibrosis with metastatic breast cancer simulating agnogenic myeloid metaplasia: report of a case and review of the literature.

A patient with carcinoma of the breast, who developed a clinical syndrome resembling agnogenic myeloid metaplasia, is described. She was found to have secondary myelofibrosis with metastatic carcinoma of the marrow, extensive extramedullary hematopoiesis resulting in massive splenomegaly, and leukoerythroblastosis. These findings are rare and myeloid metaplasia with striking extramedullary hematopoiesis causing massive splenomegaly and mimicking agnogenic myeloid metaplasia is seldom seen in patients with metastatic carcinoma. Previous case reports of secondary extramedullary hematopoiesis simulating agnogenic myeloid metaplasia (AMM) in patients with solid tumors are also reviewed.