These include histopathology consistent with AAV or positivity for serum MPO–ANCA and/or PR3-ANCA; intractable OM with effusion or granulation that will not respond to antibiotics and tympanic ventilation tubes, and exclusion of other types of OM, such as bacterial OM, choleastoma, tuberculosis, and neoplasms. Here, MPO is linked to ocular melanoma.