A case of angiomyofibroblastoma of the vulva in a 49-year-old woman was examined. The tumor measured 3 x 2.5 x 2 cm and appeared light gray to tan in color on the cut surface. Light microscopic examinations revealed that spindle or oval shaped tumor cells were arranged in loose edematous stroma with numerous thin-walled vessels. Ultrastructurally, cell organellae were not well developed but intracytoplasmic filaments of intermediate size were abundant in the tumor cells. Desmin, CD34 and vimentin immunoreactivity were detected in almost all of the tumor cells. Both estrogen and progesterone receptors were diffusely expressed in the tumor, suggestive of the sex steroid-dependency of this tumor. The KI-67 labeling index was less than 1% and the DNA content of the tumor cells, which was examined by image cytometry, demonstrated diploidy (DNA index = 0.97). These findings may reflect the quiescent or slow growing features of angiomyofibroblastoma.