Kimura's disease masquerading as parotid malignancy

Kimura's disease is a rare chronic inflammatory disease of unknown etiology, which was initially described in 19371 but popularized in 1947 by Kimura.2 Only about 200 cases have been reported in the literature hence mis-diagnosis and non-recognition are common. It generally affects the skin, soft tissues and lymphatics of the head and neck region and, rarely, it may involve other regions like retro peritoneum, groin, and trunks and limbs.3–6 The lymph node groups, especially the axillary, epitrochlear, popliteal and inguinal, may be more commonly involved. Presentation in the form of subcutaneous swellings, lymphadenopathy and recurrences after treatment being common make confusion with malignancy likely as in the presented case. All forms of treatment have been tried – including surgery, radiotherapy, immunosuppressive therapy, etc. However, there is no consensus on the correct modality in view of the limited number of reported cases and the treatment remains individualized. There is a very high incidence of recurrence following surgery or other treatment modalities.6–8 The disease more commonly affects Asian men in their second and third decades. The usual clinical features include multiple, painless, subcutaneous swellings and generalized lymphadenopathy accompanied by peripheral eosinophilia and raised serum immunoglobulins, especially IgE. Unlike most allergic disorders, the overlying skin is usually healthy. The only known systemic manifestation is renal involvement in the form of glomerulonephritis and, rarely, nephrotic syndrome. It is thought to be more common in Asia – especially in Japan and China – however, sporadic cases from the West have also been reported.3 In the presented case, on account of history of recurrence and the hard consistency of the gland associated with regional lymphadenopathy there was reason to suspect malignancy. Fine needle aspiration cytology (FNAC) was inconclusive on two occasions and the patient was treated as a suspected case of parotid malignancy. Kimura's disease was thus a histo-pathological surprise.