[Microscopic polyangiitis with eosinophilia--an overlap syndrome or separate disease entity? A case report and review of the literature].

Systemic vasculitides are potentially life-threatening diseases. Early and appropriate diagnosis based on case history, clinico-pathological features, and laboratory parameters, such as the presence of anti-neutrophil cytoplasmic antibodies (ANCA), is crucial for starting appropriate and, often, life-saving therapeutic measures. We report a 50-year-old female patient who presented with fever, arthralgias and hemoptysis. Skin signs included disseminated hemorrhagic pustules, ulcerations of oral and genital mucosa, subcutaneous nodules on arms and legs, and a pyoderma gangrenosum-like lesion on the right leg. Laboratory investigations revealed a peripheral eosinophilia and a positive cANCA titer. Histopathologic analysis of various biopsy specimens showed a granulomatous vasculitis in the subcutis, a nongranulomatous vasculitis with massive eosinophil infiltration in the lungs, and a segmental, necrotizing glomerulonephritis in the kidneys. Differential diagnosis included Wegener's granulomatosis, microscopic polyangiitis (MPA) and Churg-Strauss syndrome. MPA was diagnosed based on clinical and histopathological criteria. An interesting feature of this case was marked peripheral and tissue eosinophilia. Therapy consisted of cyclophosphamide and methylprednisolone. The patient went into a long-lasting clinical remission one month after starting therapy.