The relationship between the disorder known in Japanese and Chinese literature as Kimura's disease and that known in Western literature as angiolymphoid hyperplasia with eosinophilia (ALHE) has been the subject of debate. Many reports have used the terms synonymously. We have reviewed the histological and clinical features of 4 cases, all occurring in Caucasians, 2 of which are typical of Kimura's disease and 2 of ALHE. Analysis of the cases indicates that the histological features of the 2 disorders are sufficiently different to warrant their recognition as 2 distinct entities. The histological and clinical features of Kimura's disease are most consistent with an allergic or autoimmune process in which blood vessels, lymphocytes and eosinophils participate. Those of ALHE suggest a primary, probably neoplastic disorder of vascular endothelium with a variable and secondary inflammatory response. Although there is some clinical overlap between patients with the 2 disorders, the histological features are distinctive, and the 2 terms should not be used synonymously.

The protein encoded by the microphthalmia (mi) gene is a transcription factor essential for the development and survival of melanocytes. Using a monoclonal antibody generated against human Mi transcription factor protein (Mitf) the authors previously demonstrated that Mitf expression is conserved in primary and metastatic malignant melanomas, and appears to be a highly sensitive and specific melanocytic marker. Mitf expression in various cutaneous nevi and cutaneous nonmelanocytic tumors has not been documented systematically. The authors evaluated Mitf immunostaining in 62 benign nevi, 58 primary cutaneous melanomas, and 53 nonmelanocytic tumors. Mitf immunostaining was conserved in all benign nevi, with Spitz nevi and neurotized nevi demonstrating decreased staining intensity. With the exception of desmoplastic melanomas, all primary cutaneous melanomas were immunopositive regardless of the cell type. Only one of 14 desmoplastic melanomas was Mitf positive. None of the nonmelanocytic tumors was immunopositive, including those lesions that may resemble melanoma histologically (spindle cell carcinomas, atypical fibroxanthomas, and leiomyosarcomas). The results demonstrate that Mitf antibody expression is conserved in the majority of benign and malignant melanocytic lesions, and that it may be helpful in the diagnosis of primary melanocytic skin lesions. Its use in desmoplastic melanomas is limited and is reflective of other melanocyte-associated antigens. Mitf discriminates between spindle cell nonmelanocytic tumors and melanomas with a spindle cell morphology, and is useful in a panel with other appropriate antibodies.