Mucoepidermoid carcinoma of parotid gland and membranous nephropathy - differentiation between sclerosing mucoepidermoid carcinoma with eosinophilia and Kimura's disease.

BACKGROUND: When we encounter patients who present with both a neck mass and nephrotic syndrome, both malignancy and Kimura's disease need to be evaluated as the therapeutic strategies differ vastly between them. CASE PRESENTATION: We present the case of a 27-year-old male patient with neck mass and nephrotic syndrome. The presence of both eosinophilia and elevated immunoglobulin E levels were concerning for Kimura's disease, which is an allergic syndrome defined by eosinophilic granulomas of neck soft tissue along with peripheral eosinophilia. The eventual final diagnosis, however, was sclerosing mucoepidermoid carcinoma of parotid gland with both eosinophilia and membranous nephropathy. Following the surgical resection of the mass, the nephrotic syndrome completely resolved. CONCLUSION: Detailed histopathological assessments of both the parotid gland and renal tissue were key aspects of the diagnosis and management to exclude Kimura's disease.