A case report of minimal change disease associated with Kimura disease complicated by optic neuritis.

Kimura disease (KD) is a rare chronic inflammatory disease that typically presents with soft subcutaneous granulomas in the head and neck regions characterized by elevated blood eosinophils and immunoglobulin E (IgE) level, whose aetiology remains poorly elucidated. Minimal change disease (MCD) has been reported as one of the renal manifestations that KD can present with, indicating that they may share a common pathology. Herein we describe a case of recurrent MCD associated with KD. During a follow-up period of 15 years, MCD recurred three times with increased disease activity of KD as reflected by flares of skin lesions and elevated peripheral eosinophils, and responded well to increased doses of prednisolone and cyclosporin. Notably, visual field defects in his right monocular vision appeared at the time of third recurrence of MCD, leading to the diagnosis of optic neuritis (ON). Optic nerve involvement associated with KD is extremely rare, and this case is noteworthy in that inflammation in the optic nerve was observed at the time of MCD recurrence with increased disease activity of KD, suggesting the existence of a common pathology between KD, MCD, and ON. In patients with KD, an imbalance of T helper (Th) cells with Th2 cells predominating over Th1 cells is observed, which results in hyperIgEemia and eosinophilia. This Th2-predominant immunological status in KD considered to predispose to MCD may also predispose to ON. MCD with a background of Th2-predominant immune state may require attention to the possibility of complication of ON.