Kimura’s disease in two Caucasians, one with multiple recurrences associated with prominent IgG4 production

The aim of this study was to investigate key points for the differential diagnosis of immunoglobulin G4-related sialadenitis (IgG4-RS) and Kimura’s disease (KD) involving the salivary glands. The clinical, serological, radiological, histological, and immunohistochemical features of 85 IgG4-RS cases and 52 KD cases were evaluated comparatively. Seventy-two IgG4-RS cases had enlargement of multiple salivary and/or lacrimal glands; 67 patients had bilateral submandibular gland (SMG) involvement. Unilateral parotid gland involvement (59.6%) and comorbid skin lesions (61.5%) were common in KD. Serum IgG4 was elevated in 94.1% of IgG4-RS cases versus 19.0% of KD cases (cut-off value = 266.5 mg/dl). KD was more commonly associated with elevated eosinophil counts (86% vs 23.1%) and elevated IgE concentrations (95.5% vs 76.6%). Storiform fibrosis, irregular lymphoid follicles, and increased IgG4-positive cells (112.9 ± 37.6/high-power field (HPF)) were common in IgG4-RS. Acellular fibrosis, regular lymphoid follicles, IgE-positive reticular networks, increased IgE-positive cells (43.4 ± 26.7/HPF), and tryptase-positive mast cells (29.7 ± 13.3/HPF) were usually detected in KD. Computed tomography showed that 85.7% of KD cases involved subcutaneous fat tissue. A superficial hypoechoic and reticular pattern with multiple hypoechoic foci were the sonographic features of the SMG in IgG4-RS. Despite numerous overlapping manifestations, histopathological examination showed meaningful differences in the types of fibrosis, eosinophils, and IgG4-positive cell counts. Comprehensive evaluation of clinical, serological, radiological, and histopathological features are crucial for the differential diagnosis.

The main symptom of Kimura disease (KD), a rare, chronic inflammatory disorder of unknown etiology, is painless granulation preferentially developing in the head and neck region’s soft tissues, especially in the parotid and submandibular glands and neck lymph nodes. KD is characterized clinically by peripheral blood eosinophilia and elevated serum immunoglobulin E (IgE) levels and histopathologically by high capillary vascularization and lymphoid follicle formation with eosinophil infiltration in the connective tissues. Angiolymphoid hyperplasia with eosinophilia (ALHE), a rare benign tumor of unknown etiology, also occurs in the head and neck frequently as single/multiple angiomatous papules/nodules varying from light brown to pink. Histopathologically, accelerated endothelial cell proliferation and high lymphocyte and eosinophil infiltration are observed. Due to KD’s and ALHE’s similar clinical and pathological symptoms, differential diagnosis is challenging. Their manifestations include a painless head/neck subcutaneous swelling. Here, we have described a case involving a 44-year-old man who presented with an upper lip mass that increased in size for 1 year. Laboratory studies revealed leukocytosis and eosinophilia. Computed tomography and magnetic resonance imaging examinations revealed a submucosal lip mass. Suspect minor salivary gland malignancies and lymphomas were surgically excised. Histopathologically, we observed marked lymphoid follicle proliferation with inflammatory cell, including eosinophil infiltration, capillary proliferation, and a developed vessel not normally present in the lip. Because differentiating between KD and ALHE is difficult, clinical differentiation was our focus. The Asian male patient with lymphadenopathy, eosinophilia, and high IgE levels was finally diagnosed with KD that has not recurred in 1 year.