抄録
We report a case of infantile digital fibromatosis observed by electron microscopy. A four year-old boy was admitted to our department with a swelling on the second toe of his right foot, which first occurred at age three. Closer examination revealed a 1×1cm sized firm, red nodule in the lateral aspect of the toe. Magnetic resonance imaging (MRI) showed a soft tissue mass with low signal intensity on T1(-weighted) images, and iso signal intensity to the muscle on T2 (-weighted) images. A marginal resection was performed. The excised lesion was small firm mass that had white cut surface. Histological examination showed several cytoplasmic inclusion bodies in the spindle-shape tumor cells. Electron microscopy revealed that the inclusion bodies showed characteristics of actin filament. At follow-up examinations 10 months after surgery, no recurrence of the tumor was seen. Infantile digital fibromatosis is a fibromatosis is usually observed in feet of children less than 1 year old. Our electron microscopic study indicated that this tumor has a myofibroblastic origin.
