Case Presentation:

A 56–year–old asymptomatic male presented with a rash since 5 days. He noticed the rash on his legs which then spread to his arms. Rash was non tender and non–pruritic. Patient had chills but no fevers. Physical exam was unremarkable except for his rash. The rash was palpable and purpuric, consisted of discrete lesions on his distal arms and legs sparing his palms and soles. Routine laboratory tests revealed pancytopenia and an elevated ESR and LDH. Serum protein electrophoresis, anti–nuclear antibody and anti neutrophilic cytoplasmic antibodies were negative. Serology for hepatitis, HIV, CMV, parvovirus, were negative. Blood cultures were negative. Peripheral smear revealed one blast cell .Bone marrow biopsy showed blast cells with few Auer rods. Flow cytometry confirmed the diagnosis of AML. Skin lesion biopsy showed Leucytoclastic vasculitis. Patient was treated with chemotherapy and after a week rash had improved markedly.

Discussion:

The usual clinical signs and symptoms of Acute Myeloid Leukemia (AML) are fatigue, weight loss, hemorrhage, or infections and fever. Though cutaneous manifestations in leukemia have been reported, they rarely present as the initial symptom. Leucocytoclastic vasculitis is a small vessel vasculitis associated with hematologic malignancies, Infections, medications and chemicals. It presents as palpable purpura most often localized in the lower extremities, often accompanied by abdominal pain, arthralgia and renal involvement. Although more than half of the cases are idiopathic, the sudden appearance of leukocytoclastic vasculitis may signal an underlying systemic disease such as malignancy. leukocytoclastic vasculitis is a poorly understood paraneoplastic syndrome. Tumor associated antigens may play a key role in mediating vascular damage either indirectly by forming immune complexes or by a direct injury to the vessel wall. Circulating immune complexes occur in one–third to one–half of all patients with cancer, although neoplasms seldom lead to vasculitis. To the best of our knowledge there have been only four documented case reports where leucocytoclastic vasculitis was the initial presentation of an underlying AML.

Conclusions:

It is important to note that a diagnosis of leucocytoclastic vasculitis is not an endpoint, but rather a starting point in making a diagnosis. The take home point for physicians is that even in totally asymptomatic patients leucocytoclastic vasculitis can be the initial manifestation of AML.