Kimura Disease: An Atypical Presentation

Abstract Introduction/Objective Kimura disease is a benign, chronic inflammatory process which presents with enlarged, painless lymphadenopathy. The etiology is currently unknown. It is most commonly seen in young males of Asian descent and is rare in other populations. It typically affects the subcutaneous tissue and regional lymph nodes, as well as the orbit and adnexal tissues. Clinically, peripheral eosinophilia and increased levels of immunoglobulin are commonly seen. Histologically, the disease presents with follicular hyperplasia with germinal center formation, hyperplastic vasculature, increased eosinophilic inflammatory infiltrate, and characteristic Warthin-Finkedly cells. Methods/Case Report A 70-year-old white male with no significant past medical history presented to an outpatient clinic with a painless right eyebrow mass. The mass had grown in size which prompted the patient to seek evaluation. The decision to excise the mass was made. Upon pathologic review, hematological workup was performed, and the case was subsequently diagnosed as Kimura disease. Results (if a Case Study enter NA) The specimen was excised and H&E showed background benign fibroadipose tissue with prominent, lymphoid follicles. Within the follicles, there was a significant increase in eosinophils. Warthin- Finkeldey cells were commonly identified within germinal centers as well. Immunohistochemical staining was performed with appropriate controls which ruled out other common lymphoid malignancies and to the diagnosis of Kimura Disease. Conclusion Kimura disease is a rare, benign inflammatory disorder that most commonly affects the lymph nodes. It may be overlooked histologically when the patient does not fit the typical clinical picture. It can closely resemble neoplastic, hematologic conditions, and it should be distinguished from a more aggressive entity due to its benign, indolent behavior. From a pathologist’s point of view, because it occurs almost exclusively in young, Asian males, it is important to consider when presented with an atypical demographic to avoid unnecessary additional workup.