Solitary sclerotic neurofibroma of the skin.

Solitary neurofibroma of the skin is a benign soft tissue tumor. Clinically, it is a flesh-colored, slow-growing, soft tumor and sometimes shows diverse histological patterns. We present here a case of nontender, hard neurofibroma with sclerotic change. By transmission electron microscopic observation, some mast cells in close contact with fibroblasts and abundant collagen fibers were seen in the lesion. Our findings suggest that mast cells may have played a role in the formation of the sclerotic regions of the current tumor.