A review and update of morphologically bland vulvovaginal mesenchymal lesions.

Vulvovaginal mesenchymal lesions composed of morphologically bland spindle-shaped cells often pose a particular diagnostic problem for the surgical pathologist not only because of the rarity of these lesions but also because of the wide array of entities with overlapping morphologic features. Included in this group of lesions are soft tissue neoplasms that may arise at any site and those that are characteristic of, or relatively specific to, the vulvovaginal region. Lesions that are relatively specific to the vulvovaginal region include well-known neoplasms such as aggressive angiomyxoma and angiomyofibroblastoma as well as more recently described lesions such as cellular angiofibroma and superficial cervicovaginal myofibroblastoma. Fibroepithelial stromal polyp, superficial angiomyxoma, and smooth muscle neoplasms also can occur in, but are not specific to, this site. In this review, the clinicopathologic features of these lesions are described with an emphasis on recent developments. The value of ancillary studies, especially immunohistochemistry, is discussed, although it is stressed that in general these are of limited value and routine morphology remains the mainstay in diagnosis. Morphologically bland spindle cell lesions that are not characteristic of the vulvovaginal region, but which also may occur here, are briefly discussed as are a variety of extremely rare mesenchymal lesions that have recently been described at this site.