Case Report: Immune checkpoint inhibitor-induced IgG4-related disease mimicking renal metastatic progression: successful steroid-sparing management with rituximab

1

Immune checkpoint inhibitors can induce IgG4-related disease, a rare immune-related adverse event, following dual therapy.
2

A 65-year-old man developed IgG4-RD after treatment with nivolumab and ipilimumab for metastatic clear cell renal carcinoma.
3

Histopathological examination revealed storiform fibrosis and dense IgG4-positive plasma cell infiltration, confirming IgG4-RD.
4

Rituximab was used as a steroid-sparing first-line therapy, leading to stabilization and regression of renal lesions.
5

Histologic confirmation is essential to differentiate IgG4-RD from metastatic progression in patients receiving ICIs.

Frontiers In Immunology

by Mayara Elisa Bonatto, Jan Dvořák, Marek Kollár, David Girsa, Miroslav Průcha, Šárka Forejtová, Heřman Mann, Jiří Vencovský, Karel Pavelka, Ladislav Šenolt
July 15, 2026

1