Introduction
Spindle cell lipoma (SCL), proposed by Enzinger and Harvey [1] in 1975, is a benign soft tissue tumor. It is regarded as a subtype of lipoma composed of spindle-shaped cells and collagen fibers in various percentages among enlarged mature adipocytes. Tumor cells are positive for CD34 and negative for S-100 protein and murine double minute 2 (MDM2). Since SCL is rare, accounting for only 1.5% of lipomas [2], its characteristics remain unclear. Furthermore, SCL is often difficult to distinguish from atypical lipomatous tumors and liposarcoma in imaging examinations. Therefore, the clinical characteristics of SCL warrant further study.
Racial differences have been reported in some mesenchymal tumors, such as Kaposi’s sarcoma, dermatofibrosarcoma protuberance, angiosarcoma, and leiomyosarcoma [3], and, thus, need to be examined in each racial population. The characteristics of SCL have not yet been investigated in a single racial population. Therefore, we herein report the findings of a Japanese case of SCL and review a Japanese case series of SCL.