Concurrent Kidney Glomerular and Interstitial Lesions Associated with Kimura's Disease.

Background: Kimura disease (KD) is a chronic benign inflammatory disorder that is usually manifested as a deep, subcutaneous mass with or without regional lymphadenopathy in the head and neck region. Various types of glomerulonephritis are associated with KD, including minimal change disease (MCD), membranous glomerulopathy (MN), and immunoglobulin (Ig)A-nephropathy. Kidney interstitial lesion associated with KD is rarely reported. The aim of this study was to expand the spectrum of kidney lesions associated with KD. Methods: From 2007 to 2016, 12 cases of KD with kidney lesions were retrospectively reviewed. Pathological examinations included hematoxylin and eosin staining, periodic acid-schiff staining, periodic acid-methenamine silver staining, and Masson staining, immunofluorescence, and electron microscope analyses. Results: Anatomic sites of subcutaneous involvement included head and neck area, arm, and groin. Most cases had elevated IgE level and peripheral eosinophilia. Nephrotic syndrome was the most common kidney manifestation. Pathological results showed 3 types of glomerulonephritis, including 9 cases of MCD, 2 cases of IgA nephropathy, and 1 case of MN. Of note, 4 MCD cases showed concurrent glomerular and interstitial lesions associated with KD, including 2 distinct patterns: (1) a diffusely eosinophilic and lymphatic infiltration similar to KD lesion developed elsewhere and (2) exclusively eosinophilic infiltration in the interstitium. Eight out of 10 patients were responsive to steroid treatment and had complete remission of proteinuria and recovery of kidney function. Conclusion: Our report suggested that, in addition to glomerulonephritis, interstitial lesions may also be associated with KD. Pathologist should pay special attention to differentiated diagnosis when such pathological changes are identified in patients with subcutaneous mass or cervical lymphadenopathy with concurrent kidney manifestation.