Two cases of hypertrophic pachymeningitis associated with myeloperoxidase antineutrophil cytoplasmic autoantibody (MPO-ANCA)-positive pulmonary silicosis in tunnel workers

Two cases of hypertrophic pachymeningitis (HP) associated with pulmonary silicosis in tunnel workers are described. In both cases the myeloperoxidase antineutrophil cytoplasmic autoantibody (MPO-ANCA) was positive. Two patients with pulmonary silicosis developed headache and neurological disturbance, and a diagnosis of HP was made. In both cases the serum CRP level and the MPO-ANCA titer were elevated. Corticosteroid therapy produced a rapid improvement in all the clinical and laboratory parameters. Although an association has been noted between exposure to silica dust and ANCA-associated vasculitis, particularly glomerulonephritis, central nervous system involvement is rare. However, there have been some recent reports of HP cases that were positive for ANCA, and the association between HP and vasculitis has been discussed in the medical literature. HP may be one feature of multiorgan involvement in ANCA-associated disease, and the association between silica dust exposure and HP should be considered, as with other forms of ANCA-associated vasculitis.