Cutaneous sclerosing extramedullary hematopoietic tumor in chronic myelogenous leukemia.

Background: Extramedullary hematopoiesis is a well-documented manifestation of chronic myeloproliferative disorders, most commonly seen in chronic idiopathic myelofibrosis (agnogenic myeloid metaplasia), but rarely in chronic myelogenous leukemia. It typically occurs in the spleen and liver, but has also been described in skin. Microscopically, foci of extramedullary hematopoiesis consist of erythroid and myeloid precursors intermixed with megakaryocytes. The megakaryocytes may elaborate fibrogenic cytokines, which induce proliferation of fibroblasts. The term 'sclerosing extramedullary hematopoietic tumor' has been applied to this latter entity and its resemblance to a fibrohistiocytic neoplasm has been noted.

Methods: We report the case of a 66-year-old man, whose cutaneous sclerosing extramedullary hematopoietic tumor preceded the diagnosis of chronic myelogenous leukemia.