Cutaneous extramedullary hematopoiesis in idiopathic myelofibrosis

A 67-year-old German woman presented with a 2-month history of indolent erythematous macules and livid papulonodules of 0.5-1.5 cm in diameter scattered on her abdomen (Fig. 1). On physical examination, the patient was alert, the liver was palpable 3 cm below the right costal margin, and the spleen was enlarged 3 cm below the left costal margin. There was no lymphadenopathy. Laboratory findings disclosed the following abnormalities: hemoglobin, 10.6 g/dL; hematocrit, 32.4%; white blood cell count, 4.600/mm(3) myelocytes, with 15.2% lymphocytes, 74.1% neutrophils, 6.7% monocytes, and 3.6% eosinophils. Repeated bone marrow biopsy specimens showed severe myelofibrosis and osteosclerosis. Histologic examination of an incisional skin biopsy specimen revealed a mixed dermal infiltrate containing numerous histiocytic and myelocytic cells that resembled atypical megakaryocytes. Cells of the erythroid series were absent. The giant cells were labeled with CD61, thereby supporting the megakaryocytic lineage. The naphthol As-D chloracetate reaction was positive on myelocytic cells of the infiltrate indicating granulocytopoiesis (Fig. 2). The patient had received electron-beam irradiation 8 months previously, and had been treated with hydroxyurea (Litalir(R), 500 mg/day) for 8 months before the manifestation of myelofibrosis on the skin. Two months after her first visit to our out-patient clinic, the eruptions expanded, and electron-beam irradiation was considered, but not performed, because of the progress of the disease. The patient's course was complicated by severe bone pain, the development of anemia (2.6 g/dL), a blast crisis with 80% undifferentiated, myelocytic blasts, and thrombocytopenia (26 x 10(9)/L). Symptomatic treatment, such as several blood transfusions and analgesic agents, did not stabilize the situation. During this stage of the illness, the skin alterations remained unchanged. Sixteen months after the first diagnosis of myelofibrosis, the patient died due to conversion into chronic myelogenous leukemia, as shown by repetition of the bone marrow aspiration and the peripheral blood count.