Cutaneous Vasculitis as the Initial Manifestation in Acute Myelomonocytic Leukemia

Vasculitides are a heterogeneous group of clinical disorders that are idiopathic (polyarteritis nodosa, Wegener granulomatosis) and that may be associated with connective tissue diseases (systemic lupus erythematosus, rheumatoid arthritis, scleroderma); with sepsis; or with neoplasia [1, 2], especially leukemias and lymphomas [3-11]. In vasculitides, the basic histopathologic characteristic is inflammatory changes in vessel walls. The inflammatory infiltrate can be predominantly neutrophilic (usually accompanied by leukocytoclasis), lymphocytic, or granulomatous. Necrotizing changes (usually of fibrinoid type) of the vessel wall may be present or absent. Acute myelomonocytic leukemia is a neoplastic disorder of the granulocytic and monocytic lineage that is characterized by a mixture of immature cells, mainly myeloblasts and monoblasts in the peripheral blood and bone marrow. Patients with acute myelomonocytic leukemia may present with extramedullary neoplastic infiltrates in the liver, gingiva, skin, and central nervous system. Skin involvement in acute myelomonocytic leukemia includes three types of lesions: nonspecific, leukemic cutis, and granulocytic sarcoma [12, 13].

Nonleukemic skin vasculitis in patients with acute myelogenous leukemia has rarely been reported [9-11]. For this reason, we describe three patients presenting with skin vasculitis as the initial clinical manifestation in whom a diagnosis of acute myelomonocytic leukemia was subsequently established by peripheral blood smear and bone marrow aspirate examinations.