Clinicopathologic Characterization of IgG4-Rich Pediatric Head and Neck Lesions.

ABSTRACT

CONTEXT.­ Immunoglobulin G4 (IgG4)-related disease is rare but well characterized in adults; however, the clinical and histologic manifestations in children may differ. OBJECTIVE.­ To review the clinical and histologic features of IgG4-rich head and neck lesions in a pediatric population. DESIGN.­ Retrospective search for cases with IgG4 immunohistochemical staining performed at our institution from 2011 to 2019. Review of clinical courses, serology profiles, histologic patterns, and immunohistochemical staining patterns. RESULTS.­ Four pediatric IgG4-rich lesions were identified and showed distinct histologic patterns from adult IgG4-related disease, including absence of pathognomonic findings associated with the latter. One case showed intralesional immunoglobulin light-chain restriction. Clinical review showed serum IgG4 elevation in 2 of 4 cases, presence of additional autoantibody positivity, and a generally benign/treatment-responsive clinical course. CONCLUSIONS.­ Pediatric IgG4-related disease shows distinct clinical, serologic, and histologic features from its adult counterpart. Pediatric IgG4-related disease involving the orbit has unique clinical characteristics, including frequently normal serum IgG4 levels and female predominance. Awareness of and evaluation for these features may improve diagnosis and treatment.