Bilateral dacryoadenitis as the initial presentation of ANCA-associated vasculitis in a pediatric patient

A 14-year-old female presented with 2 weeks of progressive right eye pain, erythema, and proptosis. Examination demonstrated an enlarged palpable mass along the right superior lateral orbit and bilateral conjunctival petechiae. Of note, she was asymptomatic on the left side, and the petechiae were present only on the superior bulbar conjunctiva with eyelid eversion. Imaging demonstrated bilateral lacrimal gland enhancement. Testing was significant for elevated inflammatory markers, but otherwise negative workup. Biopsy of the right lacrimal gland demonstrated acute-on-chronic inflammation without evidence of lymphoproliferative disease. On repeat testing, myeloperoxidase antibody levels (MPO/p-ANCA) were elevated, indicative of an underlying immune-mediated vasculitis. This case illustrates a rare presentation of ANCA-associated vasculitis in a pediatric patient. It further demonstrates the phenomenon of initial negative serology and subsequent auto-antibody seroconversion in a patient with localized granulomatosis with polyangiitis.